KR102043217B1 - Power transforming apparatus, air conditioner including the same and method for controlling the same - Google Patents

Abstract

The present invention relates to a power converter, and more particularly, to a power converter including a power factor controller, an air conditioner including the same, and a control method thereof. The present invention, the rectifier for rectifying the AC voltage input from the AC power source; A power factor controller which performs a power factor improvement operation on the voltage rectified by the rectifier and includes a switching element; A DC-link capacitor storing the output voltage of the power factor controller; A gate driver for driving the switching element; A thermistor positioned on the gate driver and outputting a voltage varying with temperature; And a controller configured to apply a driving signal to the gate driver and to be connected to the thermistor to block the driving signal when an output voltage of the thermistor is smaller than a set value.

Description

Power converting apparatus, air conditioner including the same and method for controlling same {Power transforming apparatus, air conditioner including the same and method for controlling the same}

The present invention relates to a power converter, and more particularly, to a power converter including a power factor controller, an air conditioner including the same, and a control method thereof.

Generally, the compressor of an air conditioner uses a motor as a drive source. These motors are supplied with alternating current power from a power converter.

Such a power conversion device is generally known to include a rectifier, a power factor controller and an inverter.

First, the commercial voltage of the AC output from the commercial power supply is rectified by the rectifier. The rectified voltage is supplied to a power converter 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 may be provided between the rectifier and the inverter to improve power factor.

Such a converter is provided with a switching element for switching operation.

In general, a power conversion device may include a switching device implemented as a semiconductor device such as an IGBT. The switching device and / or the gate driver may overheat, although a switching device implemented by a semiconductor device such as an IGBT may have a function of protecting the switching device when an abnormal voltage such as overcurrent and overvoltage occurs. In this case, the function of protecting the switching element and / or the gate driver from such overheating may not be implemented separately.

Therefore, a method for protecting the switching element and / or the gate driver from overheating is required, and in such a case, a method for allowing a product installed with a power converter to operate without error is required.

An object of the present invention is to provide a power converter, an air conditioner including the same, and a control method capable of preventing at least one of the switching element and the gate driver from being burned out by overheating.

Another object of the present invention is to provide a power converter capable of operating an air conditioner without abnormal operation while protecting at least one of the switching element and the gate driver from overheating, an air conditioner including the same, and a control method thereof.

As a first aspect for achieving the above technical problem, the present invention, the rectifier for rectifying the AC voltage input from the AC power source; A power factor controller which performs a power factor improvement operation on the voltage rectified by the rectifier and includes a switching element; A DC-link capacitor storing the output voltage of the power factor controller; A gate driver for driving the switching element; A thermistor positioned on the gate driver and outputting a voltage varying with temperature; And a controller configured to apply a driving signal to the gate driver and to be connected to the thermistor to block the driving signal when an output voltage of the thermistor is smaller than a set value.

Here, the set value may be set in consideration of the temperature difference according to the positional difference between the thermistor and the switching element.

Here, the thermistor may be installed at a position facing each of the switching element and the gate driver in a right angle direction.

Here, the thermistor may be connected to a FO (fault out) terminal of the gate driver.

Here, when the output voltage of the thermistor is smaller than the set value, it is possible to control so that the power charged in the DC-link capacitor is transferred to the inverter as it is through the output of the rectifier.

Here, the controller may output the driving signal when the output voltage of the thermistor is equal to or greater than the set value to normally operate the power factor controller.

In the control method of the power converter including a rectifier, a power factor controller, a DC-link capacitor and an inverter, and the thermistor is installed on the side of the switching element for driving the power factor controller,

As a second aspect for achieving the technical problem, the present invention, the step of sensing the output voltage of the thermistor; Determining whether the output voltage is smaller than a set value; Stopping driving of the switching element of the power factor controller when the output voltage is smaller than a set value; And controlling the inverter to operate by using power charged in the DC-link capacitor through the rectifier.

Here, the set value may be set in consideration of the temperature difference according to the positional difference between the thermistor and the switching element.

The method may further include outputting the driving signal when the output voltage of the thermistor is equal to or greater than the set value to normally operate the power factor controller.

As a third aspect for achieving the above technical problem, the present invention can provide an air conditioner including the power converter as described above.

The present invention has the following effects.

First, it is possible to protect the switching element and / or the gate driver from overheating to prevent burnout of the switching element and / or the gate driver due to the high temperature.

In this case, the power converter may be operated in the passive state without stopping the operation. Therefore, the cooling performance of the air conditioner in which such a power converter was installed does not fall.

In addition, the power factor controller may operate normally after the overheating is resolved.

1 is a block diagram illustrating a power conversion apparatus according to an embodiment of the present invention.
2 is a circuit diagram illustrating a power conversion apparatus according to an embodiment of the present invention.
3 is a detailed circuit diagram illustrating a power conversion apparatus according to an embodiment of the present invention.
4 is a diagram illustrating an installation position of a thermistor according to an embodiment of the present invention.
5 is a flowchart illustrating a control method of a power conversion apparatus according to an embodiment of the present invention.

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

While the invention allows for various modifications and variations, specific embodiments thereof are illustrated by way of example in the drawings and will be described in detail below. However, it is not intended to be exhaustive or to limit the invention to the precise forms disclosed, but rather the invention includes all modifications, equivalents, and alternatives consistent with the spirit of the invention as defined by the claims.

When an element such as a layer, region or substrate is referred to as being on another component "on", it will be understood that it may be directly on another 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 / or regions It will be understood that it should not be limited by these terms.

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

Referring to FIGS. 1 and 2, the power converter 100 may include: a rectifier 110 rectifying the AC power source 10 and a converter 120 for boosting / stepping down the DC voltage rectified by the rectifier 110 or controlling the power factor. ), A converter controller 130 for controlling the converter 120, an inverter 140 for outputting a three-phase alternating current, an inverter controller 150 for controlling the inverter 140, and a converter 120 and an inverter 140. It may include a DC terminal capacitor (C) between.

The 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 for driving the air conditioner, the power converter 100 will be described as an example of the motor driving device for driving such a compressor motor.

However, the motor 200 is not limited to the compressor motor, and may be used in various applications using an AC voltage having a variable frequency, for example, an AC motor such as a refrigerator, a washing machine, an electric car, a car, a cleaner, and the like.

The motor driving apparatus 100 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.

The motor drive apparatus 100 receives AC power from a system, converts 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 may use a boost converter. In some cases, the converter 120 may be a concept including the rectifier 110. Hereinafter, the converter 120 will be described with an example using a boost converter.

The rectifier 110 receives the single-phase AC power supply 10 to rectify the rectifier 110 and outputs the rectified power to the converter 120. To this end, the rectifier 110 may use a full-wave rectifier circuit using a bridge diode.

As described above, the converter 120 may perform a power factor improving operation in the process of boosting and smoothing the voltage rectified by the rectifier 110.

The converter 120 includes an inductor L1 connected to the rectifier 110, a switching element Q1 connected to the inductor L1, a capacitor C connected in parallel with the switching element Q1, and The diode D1 may be connected between the switching element Q1 and the capacitor C. FIG.

The boost converter 120 is a converter capable of obtaining an output voltage higher than an input voltage. When the switching element Q1 is turned on, the diode D1 is blocked and energy is stored in the inductor L1 and stored in the capacitor C. The discharged charge discharges to generate an output voltage at the output terminal.

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

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

The converter controller 130 may include a gate driver 131 for transmitting a PWM signal to the gate terminal of the switching element Q1 and a controller 132 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).

IGBT is a switching device having a structure of a power MOSFET (metal oxide semi-conductor field effect transistor) and a bipolar transistor (bipolar transistor), the driving power is small, high speed switching, high breakdown voltage, high current density device is possible.

As such, the converter controller 130 may control the turn-on timing of the switching element Q1 in the converter 120. Accordingly, the converter control signal Sc for turning on timing of the switching element Q1 may be output.

To this end, 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 B, respectively.

In some cases, the converter 120 and the converter controller 130 may be omitted. That is, the output voltage passing through the rectifier 110 may be charged in the DC terminal capacitor C or drive the inverter 140.

The input voltage detector A may detect the input voltage Vs from the input AC power supply 10. For example, it may be located in front of the rectifying unit 110.

The input voltage detector A may include a resistor, an OP AMP, or 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 controller 130 to generate the converter control signal Sc.

Next, the input current detector D may detect the input current Is from the input AC power supply 10. Specifically, it may be located in front of the rectifier 110.

The input current detector D may include a current sensor, a current transformer (CT), a shunt resistor, or 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 controller 130 to generate the converter control signal Sc.

The DC voltage detector B detects the pulsating voltage Vdc of the DC terminal capacitor C. For such power supply detection, a resistive element, OP AMP, or the like can be used. The detected voltage Vdc of the DC terminal capacitor C may be applied to the inverter controller 150 as a discrete signal in the form of a pulse, and may be applied to the DC voltage Vdc of the DC terminal capacitor C. An inverter control signal Si may be generated based on this.

On the other hand, unlike the figure, the detected DC voltage may be applied to the converter controller 130 and used to generate the converter control signal Sc.

The inverter 140 includes a plurality of inverter switching elements Qa, Qb, Qc, Q'a, Q'b, and Q'c, and smoothes the DC power supply Vdc smoothed by an on / off operation of the switching element. May be converted into a three-phase AC power source having a predetermined frequency and output to the three-phase motor 200.

Specifically, the inverter 140 is a pair of the upper switching elements (Qa, Qb, Qc) and the lower switching elements (Q'a, Q'b, Q'c) connected in series with each other, a total of three pairs of phase The lower switching elements can be connected in parallel with each other.

Like the converter 120, the switching elements Qa, Qb, Qc, Q'a, Q'b, and Q'c of the inverter may use a power transistor, for example, an insulated gate bipolar transistor (insulated gate). bipolar mode transistor (IGBT) can be used.

The inverter controller 150 may output the inverter control signal Si to the inverter 140 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 generated based on the output current io flowing through the motor 200 and the DC terminal voltage Vdc which is both ends of the DC terminal capacitor C. Can be output. The output current io at this time may be detected from the output current detector E, and the DC terminal voltage Vdc may be detected from the DC terminal voltage detector B.

The output current detector E may detect the output current io flowing between the inverter 140 and the motor 200. That is, the current flowing through the motor 200 is detected. The output current detector 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 by using three-phase equilibrium.

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

As shown in FIG. 2, the thermistor (NTC) 133 may be connected to the converter controller 130. The thermistor 133 may output a voltage value that varies with temperature. For example, the higher the temperature, the lower the output voltage value.

In detail, the thermistor 133 may be connected to the gate driver 131 and the controller 132 of the converter controller 130, respectively. The thermistor 133 may be installed at the switching element Q1 and the gate driver 131. That is, it may be installed at a position close to the switching element Q1 and the gate driver 131.

In this case, the controller 132 may operate to apply or block a driving signal for driving the switching element Q1 according to the output voltage of the thermistor.

For example, when the output voltage of the thermistor is smaller than the set value, the driving signal of the switching element Q1 may be blocked. This matter will be described later in detail.

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

FIG. 3 mainly shows a configuration corresponding to a DC-DC converter operating as a power factor control (PFC) unit among power converters.

As described with reference to FIG. 2, the converter 120 may perform a power factor improving operation in the process of boosting and smoothing the voltage rectified by the rectifier 110.

Here, the inductor L1, the diode D1 connected between the switching element Q1 and the capacitor C as shown in FIG. 2 is omitted.

In addition, the switching element Q1 may perform a switching operation by a pulse width modulation (PWM) signal transmitted from the gate driver 131. That is, the PWM signal transmitted from the gate driver 131 may be connected to the gate terminal of the switching element Q1 to perform a switching operation by this PWM signal.

The controller 132 may transfer the PWM driving signal to the gate driver 131 to control the gate driver 131 and the switching element Q1.

The gate driver 131 includes a P-type metal-oxide semiconductor (PMOS) and an N-type MOS (NMOS) therein, and the PMOS and NMOS are turned on and off as the switching element ( A driving voltage (eg, gate-emitter voltage V _GE ) is applied to Q1, and thus the switching element Q1 may perform an on / off operation.

The gate driver 131 may be connected to the gate terminal of the switching element Q1 by the resistor R1. In addition, a power supply terminal 15V for driving may be connected to the gate driver 131.

In this case, the collector stage C of the switching element Q1 may be connected to the above-mentioned DC-link capacitor DC, and the emitter E stage of the switching element Q1 is a power supply ground terminal as an output terminal; GND).

In this way, by the operation of the switching element Q1, the voltage rectified in the rectifier 110 is boosted and smoothed according to the operation of the converter shown in FIG. 2, and the boosted and smoothed voltage is converted into the DC-link capacitor C. ) Can be stored.

As mentioned above, the thermistor (NTC) 133 may be connected to the converter controller 130. The thermistor 133 may output a voltage value that varies with temperature. For example, the higher the temperature, the lower the output voltage value.

In detail, the thermistor 133 may be connected to the gate driver 131 and the controller 132 of the converter controller 130, respectively. The thermistor 133 may be installed at the switching element Q1 and the gate driver 131. That is, it may be installed at a position close to the switching element Q1 and the gate driver 131.

In this case, the controller 132 may operate to apply or block a driving signal for driving the switching element Q1 according to the output voltage of the thermistor 133.

For example, the controller 132 may block the driving signal of the switching element Q1 when the output voltage of the thermistor 133 is smaller than the set value.

Here, the set value may be set in consideration of the temperature difference according to the positional difference between the thermistor 133 and the switching element Q1. For example, the set value may be set in consideration of the temperature difference existing between the position of the thermistor 133 and the junction temperature of the switching element Q1. That is, if a temperature difference of, for example, 5 ° C. exists between the position of the thermistor 133 and the junction temperature of the switching element Q1, the set value may be determined in consideration of the voltage difference.

4 is a diagram illustrating an installation position of a thermistor according to an embodiment of the present invention.

Referring to FIG. 4, the thermistor 133 may be installed at a position facing the switching element Q1 and the gate driver 131 in a right angle direction, respectively.

That is, the gate driver 131 may be implemented as a semiconductor integrated circuit (IC) device, and the thermistor 133 may be installed at a position close to the integrated circuit device and the switching device Q1.

Referring again to FIG. 3, the thermistor 133 may be connected to the control unit 132 and may be connected to a fault out (FO) terminal of the gate driver 131 at the same time. In this case, when a signal is output from the FO terminal of the gate driver 131, the operation of the gate driver 131 may be stopped.

In addition, the controller 132 may be connected to the input terminal IN of the gate driver 131. When the controller 132 applies an output signal to the input terminal IN of the gate driver 131, the PWM driver is not output from the gate driver 131, so that the driving of the switching element Q1 may be stopped.

As such, the controller 132 may block the driving signal of the switching element Q1 when the output voltage of the thermistor 133 is smaller than the set value. That is, when the temperature of the position where the thermistor 133 is installed increases and the output voltage of the thermistor 133 becomes smaller than the set value, the driving of the switching element Q1 may be stopped.

That is, the controller 132 senses the output voltage of the thermistor 133 and, when the temperature thereof becomes higher than the set temperature, gives an output signal to the input terminal IN of the gate driver 131 to switch device Q1. You can stop the operation of the.

On the other hand, when the output voltage of the thermistor 133 is smaller than the set value and the driving of the switching element Q1 is stopped, the control unit 132 passes through the output of the rectifying unit 110 to the DC-link capacitor C. The power charged in the control may be transferred to the inverter 140 as it is.

That is, the controller 132 may control the power conversion device to operate manually without the converter 130 (hereinafter, referred to as passive operation). Thus, the air conditioner using the power converter 100 can operate normally even when the driving of the switching element Q1 is stopped.

Subsequently, the controller 132 continuously detects the output voltage of the thermistor 133, and when the output voltage of the thermistor 133 becomes higher than or equal to the set value, that is, the temperature of the portion where the thermistor 133 is installed is adjusted to the set value. When the temperature falls below the corresponding temperature, the power factor controller 120 may be normally operated by outputting the driving signal to the gate driver 131 again.

5 is a flowchart illustrating a control method of a power conversion apparatus according to an embodiment of the present invention.

Hereinafter, the operation of the power converter having the configuration described above and the air conditioner including the same will be described.

That is, a switching element including a rectifier 110, a power factor controller 120, a DC-link capacitor C, and an inverter 140 as shown in FIGS. 1 to 4 and driving the power factor controller 120 ( The control method of the power converter 100 provided with the thermistor 133 on the Q1) side will be described in detail.

First, the controller 132 senses an output voltage of the thermistor NTC 133 (S10). As described above, the output voltage of the thermistor 133 may be simultaneously input to the FO terminal of the gate driver 131 and the controller 132.

Thereafter, the controller 132 determines whether the output voltage of the thermistor 133 is smaller than the set voltage (S20).

Specifically, it is determined whether the output voltage of the thermistor 133 is smaller than the set value in consideration of the temperature difference existing between the position of the thermistor 133 and the junction temperature of the switching element Q1. That is, it is determined whether the junction of the switching element Q1 and the gate driver 131 are overheated. As described above, the set value may be set in consideration of the temperature difference according to the positional difference between the thermistor 133 and the switching element Q1.

At this time, if the output voltage of the thermistor 133 is not smaller than the set voltage, the controller 132 normally outputs the driving signal of the gate driver 131 to drive the power factor controller 120.

On the other hand, when the output voltage of the thermistor 133 is smaller than the set value, the control unit 131 stops the signal output (S40), the driving of the switching element Q1 of the power factor control unit 120 is stopped (S50).

In this situation, as described above, the controller 131 drives the power converter 100 in a passive operation (S60). That is, although the power factor control unit 120 stops driving, the inverter 140 is controlled to operate using the power charged in the DC-link capacitor C through the rectifier 110.

The controller 131 continuously detects the output voltage of the thermistor 133. That is, the operation returns to step S10 to repeat the operation.

At this time, even during the passive operation, when the output voltage of the thermistor 133 becomes equal to or greater than the set value, the power factor controller 120 may be normally operated by outputting the driving signal to the gate driver 131 again (S30).

In general, in the power conversion device, the switching element Q1 implemented with a semiconductor element such as an IGBT may have a function of protecting the switching element Q1 when an abnormal current such as overcurrent, overvoltage, and abnormal current occur. When Q1) and / or gate driver 131 is overheated, the function of protecting switching element Q1 and / or gate driver 131 from such overheating may not be separately implemented.

According to the present invention, it is possible to protect the switching element Q1 and / or the gate driver 131 from such overheating, thereby preventing burnout of the switching element Q1 and / or the gate driver 131 due to the high temperature.

In this case, the power converter may be operated in the passive state without stopping the operation. Therefore, the cooling performance of the air conditioner in which such a power converter was installed does not fall.

In addition, after the overheating is resolved, the power factor controller 120 may operate normally.

On the other hand, the embodiments of the present invention disclosed in the specification and drawings are merely presented specific examples for clarity and are not intended to limit the scope of the present invention. It is apparent to those skilled in the art that other modifications based on the technical idea of the present invention can be carried out in addition to the embodiments disclosed herein.

100: power converter 110: rectifier
120: power factor controller, converter 130: converter controller
131: gate driver 132: controller
133: Thermistor (NTC)

Claims (10)

A rectifier for rectifying an AC voltage input from an AC power source;
A power factor controller which performs a power factor improvement operation on the voltage rectified by the rectifier and includes a switching element;
A DC-link capacitor storing the output voltage of the power factor controller;
A gate driver for driving the switching element;
A thermistor positioned on the gate driver and outputting a voltage varying with temperature; And
A control unit configured to apply a driving signal to the gate driving unit and to be connected to the thermistor to block the driving signal when an output voltage of the thermistor is smaller than a set value.
The thermistors are respectively connected to FO (fault out) terminals of the controller and the gate driver.
The control unit, when the output voltage of the thermistor is less than the set value, the power conversion device, characterized in that to control the power supplied to the DC-link capacitor is delivered to the inverter as it is through the output of the rectifier. The power converter according to claim 1, wherein the set value is set in consideration of a temperature difference according to a positional difference between the thermistor and the switching element. The power converter according to claim 1, wherein the thermistor is provided at a position facing the switching element and the gate driver in a right angle direction, respectively. delete delete The power converter of claim 1, wherein the controller is configured to output the driving signal to operate the power factor controller when the output voltage of the thermistor is equal to or greater than the set value. delete delete delete An air conditioner comprising the power converter of any one of claims 1 to 3.

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