KR20190090166A - Air conditioner having function of protection from grounding - Google Patents

Abstract

The present invention relates to an air conditioner and, particularly, to an air conditioner having a protection function for a ground fault. The air conditioner including a protection function for a ground fault comprises: an outdoor unit of an air conditioner; a rectification unit installed in the outdoor unit of an air conditioner and rectifying alternating current (AC) power; a power factor control unit connected to the rectification unit and performing power factor improvement operation for a signal outputted from the rectification unit including a switching element; a direct current (DC)-link capacitor in which output voltage of the power factor control unit is stored; an inverter module including the plurality of switching elements using the voltage stored in the DC-link capacitor to generate three-phase AC current for driving a motor and a driving unit driving the plurality of switching elements; and a ground fault protection unit installed between the DC-link capacitor and the inverter module to detect a ground fault occurrence so as to protect the inverter module from overcurrent.

Description

[0001] The present invention relates to an air conditioner having a ground fault protection function,

The present invention relates to an air conditioner, and more particularly, to an air conditioner having a protection function against a ground fault.

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.

In this way, the compressor operates according to the operation of the motor driven by the inverter, and the circulation cycle of the refrigerant in the air conditioner is performed.

In some cases, an electric anomaly may occur in the power conversion apparatus including the inverter. For example, overcurrent and overvoltage may be applied. Such overcurrent and overvoltage can be caused by various causes.

Of these many causes, arm shorts and line shorts are typically detectable using shunt resistors.

However, when a ground fault occurs, at least a part of the current flowing into the inverter flows in a different path without reflux.

That is, when a ground fault occurs, at least a part of the current flowing into the inverter flows through the external path, and the shunt resistor can not detect it.

Therefore, there is a need for a method that can effectively detect such a ground fault and protect the power inverter.

SUMMARY OF THE INVENTION An object of the present invention is to provide an air conditioner having a ground fault protection function capable of protecting at least one of an inverter, a motor, and a power conversion device from a ground fault.

The present invention also provides an air conditioner having a ground fault protection function capable of performing a detection and protection function without supplying a separate power source when a ground fault occurs.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, unless further departing from the spirit and scope of the invention as defined by the appended claims. It will be possible.

According to a first aspect of the present invention, there is provided an air conditioner capable of protecting at least one of a power conversion device, an inverter, and a compressor motor by detecting occurrence of a ground fault in the air conditioner.

According to the first aspect of the present invention, there is provided an air conditioner including a protection function against a ground fault, the air conditioner comprising: an outdoor unit; A rectifying unit installed in the outdoor unit and rectifying AC power; A power factor control unit connected to the rectifying unit and including a switching element to perform a power factor improving operation on a signal output from the rectifying unit; A DC-link capacitor for storing an output voltage of the power factor control unit; An inverter module including a plurality of switching elements for generating a three-phase alternating current for driving a motor using a voltage stored in the DC-link capacitor, and a driving unit for driving the plurality of switching elements; And a ground protection unit installed between the DC-link capacitor and the inverter module to detect a ground fault and protect the inverter module from an overcurrent caused by a ground fault.

The ground fault protection unit may include a first current sensing unit installed on an active line between the DC-link capacitor and the inverter module to sense a direct current; And a control unit for interrupting a driving signal transmitted to the inverter module according to a current sensing amount of the first current sensing unit. Therefore, the inverter module can be protected by detecting the overcurrent of the active line.

The ground fault protection unit may further include a second current sensing unit installed in a neutral line between the DC-link capacitor and the inverter module to sense a DC current.

Also, the controller may block the driving signal transmitted to the inverter module by comparing the sensing current of the first current sensing unit and the current sensed by the second current sensing unit. In this manner, the ground fault can be determined by comparing the current of the active line with the current of the neutral line.

The ground fault protection unit may further include a third current sensing unit installed in the housing of the compressor motor. The ground fault protection unit may further include a fourth current sensing unit installed in the housing of the outdoor unit.

Also, at least one of the third current sensing unit and the fourth current sensing unit may output a voltage signal corresponding to the amount of sensing current. In this way, the third current sensing unit and the fourth current sensing unit can transmit a voltage signal to the control unit without being directly connected to the power conversion device.

In addition, the controller may block a drive signal transmitted to the inverter module when the magnitude of the output voltage signal of at least one of the third current sensing unit and the fourth current sensing unit is equal to or greater than a set value. At this time, the ground can be judged even if the overcurrent is not detected in the current of the active line.

The ground fault protection unit may sense a voltage signal output from at least one of the third current sensing unit and the fourth current sensing unit to indicate a portion where the ground fault occurs.

According to a second aspect of the present invention, there is provided a method of controlling at least one of a power converter, an inverter, and a compressor motor by detecting and comparing a current amount of an active line and a current amount of a neutral line refluxed through the inverter module, An air conditioner can be provided.

According to a second aspect of the present invention, there is provided an air conditioner including an outdoor unit including a compressor motor and including a protection function against a ground fault, the air conditioner comprising: a rectifying unit for rectifying AC power; A power factor control unit connected to the rectifying unit and including a switching element to perform a power factor improving operation on a signal output from the rectifying unit; A DC-link capacitor for storing an output voltage of the power factor control unit; An inverter module including a plurality of switching elements for generating a three-phase alternating current for driving a motor using a voltage stored in the DC-link capacitor, and a driving unit for driving the plurality of switching elements; And a ground protection unit for detecting and comparing a current amount of an active line between the DC-link capacitor and the inverter module and a current amount of a neutral line refluxed through the inverter module to determine a ground fault, thereby blocking a drive signal transmitted to the inverter module .

The ground fault protection unit may detect at least one of an amount of current flowing through the housing of the compressor motor and an amount of current flowing through the housing of the outdoor unit to determine a ground fault.

The ground fault protection unit may indicate a portion where the ground fault occurs when the amount of current flowing through the housing of the compressor motor and the amount of current flowing through the housing of the outdoor unit is equal to or greater than a set value.

The present invention has the following effects.

First, at least one of the inverter module, the compressor, and the power conversion device can be protected when the overcurrent occurs due to the operation of the ground fault protection portion.

In addition, it is possible to protect at least one of the inverter module, the compressor, and the power conversion device as well as the operator by detecting the amount of the current that is refluxed even when the overcurrent does not occur to determine whether or not the ground fault has occurred.

That is, by notifying the occurrence of a ground fault, the operator can recognize that a short circuit has occurred in a portion other than the electric transmission line, and can perform the operation using the protection means.

Moreover, by displaying the ground fault occurrence portion, the operator can more easily find the cause of the ground fault and perform work such as repair.

Further scope of applicability of the present invention will become apparent from the following detailed description. It should be understood, however, that the detailed description and specific examples, such as the preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art.

1 is a block diagram showing a power converter of an air conditioner which can be applied to an embodiment of the present invention.
2 is a circuit diagram showing an air conditioner according to an embodiment of the present invention.
3 is a schematic view showing a phenomenon in which the air conditioner is subjected to a cancer short-circuit.
4 is a schematic view showing a line short circuit phenomenon of the air conditioner.
5 is a flowchart showing the operation of a ground fault protection unit according to an embodiment of the present invention.
6 is a detailed flowchart showing the operation of the ground fault protection unit according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein like reference numerals are used to designate identical or similar elements, and redundant description thereof will be omitted. The suffix "module" and " part "for the components used in the following description are given or mixed in consideration of ease of specification, and do not have their own meaning or role. In the following description of the embodiments of the present invention, a detailed description of related arts will be omitted when it is determined that the gist of the embodiments disclosed herein may be blurred. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. , ≪ / RTI > equivalents, and alternatives.

Terms including ordinals, such as first, second, etc., may be used to describe various elements, but the elements are not limited to these terms. The terms are used only for the purpose of distinguishing one component from another.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The singular expressions include plural expressions unless the context clearly dictates otherwise.

In the present application, the terms "comprises", "having", and the like are used to specify that a feature, a number, a step, an operation, an element, a component, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

1 is a block diagram showing a power converter of an air conditioner which can be applied to an embodiment of the present invention. Such a power conversion device may be included in the outdoor unit of the air conditioner.

1, a power conversion apparatus 100 for driving a motor 200 or a compressor 210 (see FIG. 2) driven by the motor 200 includes a rectifier 110 for rectifying an AC power source 10, A converter 120 for controlling the power factor in the process of increasing / decreasing the DC voltage rectified by the rectifier 110, a converter controller 130 for controlling the converter 120, an inverter 140 for outputting the three- An inverter control unit 150 for controlling the inverter 140 and a DC-link capacitor C between the converter 120 and the inverter 140.

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. Accordingly, the motor drive apparatus and the power conversion apparatus will be described with reference to the same reference numeral 100. Fig.

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 AC power source 10 and outputs the rectified power to the converter 120 side.

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

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.

In this way, the converter control unit 130 can control the turn-on timing of the switching element Q1 (see FIG. 2) 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 converts the smoothed DC power supply Vdc into a three-phase AC power having a predetermined frequency by the ON / OFF operation of the switching element Q1 of the converter 120, have.

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.

The inverter controller 150 includes a gate driver 142 for transmitting a PWM signal to the gate of the switching elements Qa, Qb, Qc, Q'a, Q'b and Q'c included in the inverter 140. (See FIG. 2), and a control unit 151 for transmitting a driving signal to the driving unit 142.

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 is a circuit diagram showing an air conditioner according to an embodiment of the present invention. Specifically, the configuration shown in Fig. 2 may be a configuration of an outdoor unit of the air conditioner.

Referring to FIG. 2, there is shown a specific circuit configuration for protecting a compressor 210 driven by a motor 200 (see FIG. 1).

The rectifying unit 110 can use a full-wave rectifying circuit using a bridge diode.

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 Q2 connected between the switching element Q1 and the DC- And may include a diode D1.

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 gate (or base) terminal of the switching element Q1, and the switching operation can be performed by the PWM signal.

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.

The inverter module 141 includes a plurality of inverter switching elements Qa, Qb, Qc, Qa ', Qb', and Qc ', and is turned on / off by the switching element Q1 of the converter 120 Phase AC power source having a predetermined frequency and outputs the converted three-phase AC power to the three-phase motor 200. [

Specifically, the inverter module 141 is a pair of upper switching elements Qa, Qb, and Qc and lower switching elements Qa ', Qb', and Qc 'that are serially connected to each other, and three pairs of upper and lower The switching elements can be connected to each other in parallel.

The switching elements Qa, Qb, Qc, Q'a, Q'b, and Q'c of the inverter module 141 can use power transistors as in the converter 120. For example, An insulated gate bipolar mode transistor (IGBT) may be used.

The inverter module 141 is an integrated power module (IPM) having a driving unit 142 for driving the switching elements Qa, Qb, Qc, Q'a, Q'b and Q'c .

At this time, the control unit 165 may output an inverter control signal for controlling the driving unit 142 to the inverter module 141. As mentioned above, such an inverter control signal may be a switching control signal of a pulse width modulation (PWM) scheme.

The control unit 165 may be the same element as the inverter control unit 150 described above or may be a part of the inverter control unit 150. For example, the inverter control unit 150 may include a driving unit 142 and a control unit 165.

The control unit 165 may perform a function of a ground fault protection unit 160 that detects a ground fault and can protect at least one of the power conversion apparatus, the inverter module 141, and the compressor motor 210. That is, the control unit 165 may function as a part of the ground fault protection unit 160.

The ground fault protection unit 160 may be installed between the DC-link capacitor C and the inverter module 141 to detect the occurrence of a ground fault, thereby protecting the inverter module 141 from an overcurrent caused by a ground fault.

The ground fault protection unit 160 can protect the inverter module 141 from a ground fault.

Grounding phenomenon is a phenomenon in which the insulation between the electric transmission path and the ground is reduced and bridged by an arc or a conductive material, and a dangerous voltage appears to the outside of the electric transmission path or the apparatus, Phenomenon. The current at this time is referred to as a ground fault current, and this phenomenon is generally referred to as a short circuit.

If a ground fault occurs in the electric transmission path, it may cause an electric shock hazard or electric power equipment damage. If insulation of the electric transmission path is deteriorated and damaged, for example, if a ground fault current is generated through the motor housing, If a person comes into contact with it, it can cause electric shock disaster.

Typically, arm shorts and line shorts in an air conditioner outdoor unit can be sensed using shunt resistors.

Fig. 3 is a schematic view showing the phenomenon of a female short circuit of the air conditioner, and Fig. 4 is a schematic diagram showing a line short circuit phenomenon of the air conditioner.

3, the arm short-circuit phenomenon occurs in the inverter 140 through the upper-side element and the lower-side element, for example, the upper-side element Qa and the lower-side element Qa 'of the U phase, It is a phenomenon that current flows.

In this manner, when a short circuit occurs, the current can not flow through the motor 200, and the current can be circulated to generate an overcurrent. The reflux current a can be sensed through a shunt resistor (not shown) installed near the lower-side element Qa 'of the U phase.

Referring to FIG. 4, a line short circuit is a phenomenon in which a short circuit occurs between the inverter 140 and the motor 200. Even in this case, the current can not flow through the motor 200 and may be refluxed to generate an overcurrent.

In Fig. 4, a short circuit occurs between the U-phase and the V-phase, and a current passing through the upper-side element Qa of the U-phase is refluxed through the lower-side element Qb 'of the V-phase. Likewise, the current (b) thus circulated can be sensed through a shunt resistor (not shown) installed near the lower-side element Qa 'of the U phase.

The arm short phenomenon in Fig. 3 and the line short circuit phenomenon in Fig. 4 cause the same overcurrent, but can be detected by the shunt resistor, as described above. When the overcurrent is detected, the inverter 140 and the motor 200 can be protected by stopping the operation of the inverter 140.

Referring to FIG. 2 again, when a ground fault occurs, at least a part of the current flowing into the inverter module 141 flows into another path without being refluxed.

That is, when a ground fault occurs, at least a part of the current flowing into the inverter module 141 flows to the housing of the compressor 210 or the housing of the outdoor unit 300, I will not.

Such a ground fault phenomenon can be determined by detecting the amount of current of the live line, and it is also possible to detect and determine the amount of current of the neutral line refluxed through the inverter module 141. Such a neutral line may be referred to as a ground line.

At this time, it is advantageous that the detected current amount is a direct current (DC) current. Therefore, the amount of current of the active line sensed in this way may be the amount of current between the DC-link capacitor C and the inverter module 141.

That is, the ground fault protection unit 160 senses the amount of current of the active line between the DC-link capacitor C and the inverter module 141 or detects the amount of current of the neutral line refluxed through the inverter module 141, It is possible to protect the inverter module 141 from the electric power. At this time, if a ground fault occurs, the ground fault protection unit 160 may block the drive signal transmitted to the inverter module 141.

Specifically, the ground-fault protection unit 160 includes a first current sensing unit 161 installed on an active line between the DC-link capacitor C and the inverter module 141 to sense a DC current, And a control unit 165 for interrupting a driving signal transmitted to the inverter module 141 according to the current sensing amount of the inverter 161.

Therefore, it is possible to protect the inverter module 141 by detecting the overcurrent of the active line using the ground fault protection unit 160. In addition, components such as a microcomputer implementing the control unit 165 sensitive to overvoltage and overcurrent can be protected. The inverter module 141, the power inverter 100, the compressor 210, the control unit 165, and the like are selectively described in the configuration protected by the ground fault protection unit 160. However, , And the present invention is not limited thereto.

The ground fault protection unit 160 may further include a second current sensing unit 164 installed in a neutral line between the DC-link capacitor C and the inverter module 141 to sense a direct current.

At this time, the control unit 165 may block the driving signal transmitted to the inverter module 141 by comparing the sensing current of the first current sensing unit 161 with the current sensed by the second current sensing unit 164. In this manner, the ground fault can be determined by comparing the current of the active line with the current of the neutral line.

For example, when the difference between the sense current of the first current sensing unit 161 and the current sensed by the second current sensing unit 164 is equal to or greater than a predetermined value, the controller 165 may determine that the ground fault occurs. This will be described in detail later.

Since the first current sensing unit 161 and the second current sensing unit 164 do not require a separate power source such as the SMPS and can operate using the same power supplied to the control unit 165, There is an easy advantage.

The ground fault protection unit 160 may further include a third current sensing unit 162 installed in the housing of the compressor motor 210. The ground fault protection unit 160 may further include a fourth current sensing unit 163 installed in the housing of the outdoor unit 300.

Through the third current sensing unit 162 and the fourth current sensing unit 163, the cause of the ground fault can be easily detected. For example, it is possible to relatively clearly determine where a short circuit occurs.

Also, at least one of the third current sensing unit 162 and the fourth current sensing unit 163 may output a voltage signal corresponding to the amount of sensing current. For example, the third current sensing unit 162 and the fourth current sensing unit 163 may be provided to transmit the voltage signal to the controller 165 without being directly connected to the power converter circuit.

At this time, when the magnitude of the output voltage signal of at least one of the third current sensing unit 162 and the fourth current sensing unit 163 is equal to or larger than a set value, the control unit 165 outputs the driving signal . At this time, the ground can be judged even if the overcurrent is not detected in the current of the active line.

That is, if an overcurrent is detected in the first current sensing unit 161, the driving signal transmitted to the inverter module 141 can be interrupted regardless of whether a ground fault occurs or not. However, even when the overcurrent is not detected in the first current sensing unit 161, the control unit 165 may determine that the ground fault has occurred and block the drive signal transmitted to the inverter module 141. [

The ground fault protection unit 160 senses the voltage signals Vc and Vh output from at least one of the third current sensing unit 162 and the fourth current sensing unit 163, Can be displayed.

For example, when the control unit 165 detects that the voltage signals Vc and Vh output from at least one of the third current sensing unit 162 and the fourth current sensing unit 163 are equal to or greater than the preset value, The portion for transmitting the voltage signals Vc and Vh described above can be displayed.

For example, a display panel, an LED lamp, a sound, or the like may be used as the means for displaying the ground fault occurrence portion, but the present invention is not limited thereto.

As described above, according to the embodiment of the present invention, at least one of the inverter module 141, the compressor 210, and the power conversion apparatus can be protected when the overcurrent occurs due to the operation of the ground fault protection unit 160.

In addition, it is possible to protect at least one of the inverter module 141, the compressor 210, and the power conversion apparatus as well as the operator by detecting the amount of current that is refluxed even if the overcurrent does not occur.

That is, by notifying the occurrence of a ground fault, the operator can recognize that a short circuit has occurred in a portion other than the electric transmission line, and can perform the operation using the protection means.

Moreover, by displaying the ground fault occurrence portion, the operator can more easily find the cause of the ground fault and perform work such as repair.

In this manner, the portion where the ground fault occurs when the ground fault occurs can be clearly known, and the operator can take care of occurrence of the ground fault and work.

5 is a flowchart showing the operation of a ground fault protection unit according to an embodiment of the present invention. 6 is a detailed flowchart showing the operation of the ground fault protection unit according to the embodiment of the present invention.

Hereinafter, the operation of the present invention will be described in detail with reference to Figs. 2, 5, and 6. Fig.

First, the outdoor unit is driven (S10) to drive the air conditioner.

The process described below may be performed in the ground fault protection unit 160 or the control unit 165. [

Thereafter, at least one of a process of sensing the current flowing through the active line and a process of sensing the current of the neutral line may be performed (S20).

If only the process of detecting the current flowing through the active line is performed, the protection operation can be performed when the overcurrent occurs in the power conversion device installed in the outdoor unit. At this time, the protection operation may be to block the driving signal transmitted from the control unit 165 to the driving unit 142 of the inverter module 141.

As described above, the detection of the current flowing through the active line can be performed by the first current sensing unit 161, and the sensing of the current flowing through the neutral line can be performed by the second current sensing unit 164.

Hereinafter, a process of detecting the current flowing through the active line and a process of detecting the current of the neutral line will be described.

Next, a process of determining whether an overcurrent is generated in the active line can be performed (S30).

At this time, if it is determined that an overcurrent occurs, the drive signal transmitted to the inverter module 141 may be cut off (S50).

On the other hand, if no overcurrent is generated, it is possible to perform a process (S40) of determining whether a value obtained by subtracting the amount of current flowing through the neutral line from the amount of current flowing through the active line is equal to or greater than a set value.

At this time, if the value obtained by subtracting the amount of current flowing through the neutral line from the amount of current flowing through the active line is equal to or larger than the set value, the drive signal transmitted to the inverter module 141 can be blocked (S50).

On the other hand, if the value obtained by subtracting the amount of current flowing through the neutral line from the amount of current flowing through the active line is not equal to or greater than the preset value, the process returns to step S20 and the subsequent process can be performed.

After the drive signal transmitted to the inverter module 141 is interrupted (S50), a step S60 of displaying the ground fault occurrence portion may be performed.

The step S60 of displaying the ground fault occurrence part may specifically include the following processes.

That is, referring to FIG. 6, first, the current flowing in the motor housing and the current flowing in the outdoor unit housing can be sensed (S61).

Thereafter, it is determined whether at least one of the amount of current flowing through the motor housing and the amount of current flowing through the outdoor unit housing is equal to or greater than a predetermined value (S62). As described above, the amount of current flowing in the motor housing and the amount of current flowing in the outdoor unit housing can be performed through the third current sensing unit 162 and the fourth current sensing unit 163, respectively.

The third current sensing unit 162 and the fourth current sensing unit 163 may transmit the voltage signals Vc and Vh having a magnitude corresponding to the detected current amount to the controller 165. Accordingly, the control unit 165 can determine whether or not a short circuit has occurred in the corresponding portion.

At this time, if at least one of the current flowing through the motor housing and the current flowing through the outdoor unit housing is equal to or larger than the predetermined value, the corresponding portion can be displayed (S63).

For example, when it is determined that the amount of current flowing through the motor housing is equal to or greater than the set value, it is determined that a short circuit has occurred through the motor housing and it can be displayed.

On the other hand, when it is determined that the amount of current flowing through the outdoor unit housing is equal to or larger than the set value, it is determined that a short circuit is caused to occur through the outdoor unit housing and can be displayed.

On the other hand, if at least one of the current flowing through the motor housing and the current flowing through the outdoor housing is smaller than the preset value, the process returns to step S61 and the current sensing process can be repeated.

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 141: Inverter module
142: Driving unit 150:
160: ground fault protection unit 161: first current sensing unit
164: second current sensing unit 162: third current sensing unit
163: fourth current sensing unit 165:
210: compressor 300: outdoor unit

Claims (12)

In an air conditioner including a protection function against a ground fault,
Outdoor unit;
A rectifying unit installed in the outdoor unit and rectifying AC power;
A power factor control unit connected to the rectifying unit and including a switching element to perform a power factor improving operation on a signal output from the rectifying unit;
A DC-link capacitor for storing an output voltage of the power factor control unit;
An inverter module including a plurality of switching elements for generating a three-phase alternating current for driving a motor using a voltage stored in the DC-link capacitor, and a driving unit for driving the plurality of switching elements; And
And a ground protection unit installed between the DC-link capacitor and the inverter module for detecting a ground fault to protect the inverter module from an overcurrent caused by a ground fault. group. The apparatus according to claim 1, wherein the ground-
A first current sensing part installed on an active line between the DC-link capacitor and the inverter module to sense a direct current; And
And a controller for blocking a driving signal transmitted to the inverter module according to a current sensing amount of the first current sensing unit. The apparatus according to claim 2, wherein the ground-
Further comprising a second current sensing unit installed at a neutral line between the DC-link capacitor and the inverter module to sense a DC current. The inverter according to claim 3, wherein the control unit compares the sensed current of the first current sensing unit and the sensed current of the second current sensing unit to block the drive signal transmitted to the inverter module Air conditioner with protection function. The apparatus according to claim 3, wherein the ground-
And a third current sensing unit installed in the housing of the compressor motor. The apparatus according to claim 5, wherein the ground-
The air conditioner according to claim 1, further comprising a fourth current sensing unit installed in the housing of the outdoor unit. The air conditioner according to claim 6, wherein at least one of the third current sensing unit and the fourth current sensing unit outputs a voltage signal according to an amount of sensing current. The inverter module according to claim 7, wherein the control unit interrupts a drive signal transmitted to the inverter module when the magnitude of the output voltage signal of at least one of the third current sensing unit and the fourth current sensing unit is equal to or greater than a set value The air conditioner comprising a protection against ground fault. The method according to claim 6, wherein the ground fault protection unit senses a voltage signal output from at least one of the third current sensing unit and the fourth current sensing unit, The air conditioning system comprising: An air conditioner including an outdoor unit including a compressor motor and including a protection function against a ground fault,
A rectifying part for rectifying AC power;
A power factor control unit connected to the rectifying unit and including a switching element to perform a power factor improving operation on a signal output from the rectifying unit;
A DC-link capacitor for storing an output voltage of the power factor control unit;
An inverter module including a plurality of switching elements for generating a three-phase alternating current for driving a motor using a voltage stored in the DC-link capacitor, and a driving unit for driving the plurality of switching elements; And
And a ground protection unit for sensing and comparing a current amount of an active line between the DC-link capacitor and the inverter module and a current amount of a neutral line reflowed through the inverter module to determine a ground fault and blocking a drive signal transmitted to the inverter module Wherein the air conditioner comprises a protection function against a ground fault. The ground fault protection system of claim 10, wherein the ground fault protection unit further detects at least one of an amount of current flowing through the housing of the compressor motor and an amount of current flowing through the housing of the outdoor unit, Air conditioner. The ground fault protection apparatus according to claim 10, wherein the ground fault protection section indicates a portion where the ground fault occurs when the amount of current flowing through the housing of the compressor motor and the amount of current flowing through the housing of the outdoor unit are equal to or greater than a set value And an air conditioner.

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