JP2001141795A - Insulation degradation detection device for compressor in air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the insulation degradation of a compressor motor in an air conditioner and to give an alarm to the outside before an insulation degradation causes an operation impossibility. SOLUTION: This insulation degradation detection device comprises a three- phase AC power source 1, a diode bridge 2, a filter circuit 5, a power converter 6, a compressor 7, the motor 8, an inverter control part 9 sending a pulse for PWM control, a DC part voltage sensor 10, an insulation resistance degradation decision part 12, a motor current sensor 11 and an alarm part 13. By sending a pulse from an arbitrary phase of the upper arm of the power converter 6 when the compressor 7 stops, getting a insulation resistance from a voltage in a DC voltage part and a current flowing by the pulse, comparing the insulation resistance with an insulation resistance set value to detect the insulation degradation, and giving an alarm to the outside, measures can be executed before the operation continuance as the air conditioner becomes impossible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulation failure detecting device for detecting an insulation failure, and more particularly to early detection of insulation deterioration of a compressor motor mounted on an air conditioner driven by an inverter, The present invention relates to an insulation deterioration detection device for issuing an alarm.

[0002]

2. Description of the Related Art In many years, a motor built in a compressor mounted on an air conditioner has a problem in that insulation performance is deteriorated due to combined deterioration of heat, vibration, moisture absorption and the like, resulting in burning. is there. To diagnose the insulation deterioration, turn off the air conditioner, apply a voltage to the coil from another DC or AC power supply, and use a megger (see FIG. 6) to measure the insulation resistance or dielectric loss tangent (tan δ). Is measured to diagnose insulation failure.

FIG. 5 is a diagram showing a conventional insulation failure detection method for performing insulation diagnosis of a motor such as a compressor. In the figure, 51 is a stator of a rotating machine, and 52 is a rotor.
53 is a compressor main body to which the motor is fixed. Reference numerals 51a, 51b and 51c denote stator coils provided in the iron core slots of the stator 51. One end of the stator coil 51a is commonly connected to one end of the stator coil 51c to form a U-phase terminal 55. One end of the stator coil 51b is commonly connected to the other end of the stator coil 51c to form a V-phase terminal 56, and the other end of the stator coil 51a and the other end of the stator coil 51b are commonly connected to a W-phase terminal. 57. The U-phase terminal 55, the V-phase terminal 56, and the W-phase terminal 57 are connected to the power converter 6 of FIG.

FIG. 6 is a diagram showing a measuring device 40 such as a megger used for insulation diagnosis. The measuring device 40 includes two alligator clips 41 and 42, one of which is connected to the application lead 41a and the other of which is the connection-side lead 42a.
It is connected to the.

[0005] When performing insulation diagnosis, the connection between the power converter 6 and the motor 8 in the compressor as shown in the figure is disconnected.
Thereafter, the alligator clip 41 of the application lead 41a of the measuring instrument 40 of FIG. 6 is clipped to the U-phase terminal 55 of the motor,
The alligator clip 42 of the grounding-side lead 42a is clipped to the chassis to which the compressor is fixed, and the measurement is started by the measuring instrument 40. After the stabilization time of several seconds to one minute, the stator coils 51a to The insulation resistance between the group of 51c and the chassis is measured.

[0006]

However, unlike an elevator or the like, an air conditioner is not always inspected at a fixed interval, but is inspected when the compressor becomes inoperable. It was not possible to know the precursor in advance.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and the operation of an air conditioner becomes inoperable by detecting the deterioration of insulation of a motor built in a compressor at an early stage and notifying the deterioration to the outside. The purpose is to prevent the situation.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a power converter for converting an alternating current into a direct current and converting the obtained direct current into an alternating current by a compressor driving motor in the air conditioner. In what is being used, a three-phase AC power supply and a diode bridge for converting the three-phase AC voltage of the three-phase AC power supply to DC, a filter circuit including a reactor and an electrolytic capacitor and absorbing a ripple included in the diode bridge, A power converter that converts a DC voltage output from the filter circuit to an arbitrary voltage and frequency, a motor driven by an AC voltage output from the power converter, and the air-conditioning apparatus incorporating the motor. When the compressor is installed, when the compressor is driven, a pulse for PWM control of the power converter is transmitted to stop the compressor. An inverter control unit that transmits a pulse only to the upper arm of the phase, a DC unit voltage detector that detects a voltage of a DC unit that is an output of the filter unit, and outputs the voltage to the inverter control unit and an insulation resistance deterioration determination unit; A current detector that detects a motor current flowing to the inverter control unit and the insulation resistance deterioration determination unit, and calculates an insulation resistance from outputs of the DC unit voltage detector and the motor current detector when the motor stops, and calculates an insulation resistance in advance. The set insulation resistance set value is compared, an insulation resistance deterioration judgment unit that notifies insulation deterioration when the insulation resistance calculated with respect to the set value is reduced, and an external alarm from the output of the insulation resistance deterioration judgment unit. It is provided with an alarm unit for outputting.

[0009] Alternatively, a compressor driving motor in an air conditioner uses a power converter for converting alternating current into direct current and converting the obtained direct current into alternating current. A diode bridge that converts a three-phase AC voltage of an AC power supply into DC, a filter circuit that includes a reactor and an electrolytic capacitor and absorbs a ripple included in the diode bridge, and converts a DC voltage output from the filter circuit to an arbitrary voltage and frequency. A motor driven by an AC voltage output from the power converter, a compressor incorporated in the air conditioner incorporating the motor, and the power when the compressor is driven. Invar that sends a pulse for PWM control of the converter and sends a pulse only to the upper arm of a certain phase when the compressor is stopped A control unit, a DC detector that detects a motor current flowing through the motor and outputs the detected current to the inverter control unit and the insulation resistance deterioration determination unit, and determines an insulation resistance from a DC voltage set value and an output of the motor current detector when the motor stops. Calculate, compare with a preset insulation resistance set value, insulation resistance deterioration determination unit that outputs an alarm that notifies insulation deterioration when the insulation resistance calculated with respect to the set value decreases, insulation resistance deterioration determination unit And an alarm unit for notifying the outside of the insulation resistance from the output.

[0010] Alternatively, the compressor driving motor in the air conditioner uses a power converter for converting AC to DC and converting the obtained DC to AC. A diode bridge that converts a three-phase AC voltage of an AC power supply into DC, a filter circuit that includes a reactor and an electrolytic capacitor and absorbs a ripple included in the diode bridge, and converts a DC voltage output from the filter circuit to an arbitrary voltage and frequency. A motor driven by an AC voltage output from the power converter, a compressor incorporated in the air conditioner incorporating the motor, and the power converter during operation of the compressor. A pulse for sending a pulse for PWM control of the compressor and outputting a DC voltage from the upper arm of one phase when the compressor is stopped. A DC control unit, a DC unit voltage detector that detects a voltage of the DC unit that is an output of the filter unit and outputs the voltage to the inverter control unit and the insulation resistance deterioration determination unit, and a motor current that flows through the motor. A current detector that outputs to the inverter control unit and the insulation resistance deterioration determination unit, and calculates the insulation resistance from the output of the DC unit voltage detector and the motor current detector when the motor is stopped, and compares the insulation resistance with a set value possessed therein. An insulation resistance deterioration judgment unit that outputs an alarm that notifies insulation deterioration when the insulation resistance calculated with respect to the set value decreases, and an alarm unit that notifies the outside of insulation resistance deterioration from the output of the insulation resistance deterioration judgment unit. It is provided.

In this way, it is possible to detect the deterioration of the insulation of the motor built in the compressor in the air conditioner at an early stage and to notify the outside to prevent the state in which the operation becomes impossible.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention utilizes a power converter in which a compressor driving motor in an air conditioner converts AC into DC and converts obtained DC into AC. Wherein a three-phase AC power supply and a diode bridge for converting the three-phase AC voltage of the three-phase AC power supply to DC, a filter circuit comprising a reactor and an electrolytic capacitor and absorbing a ripple included in the diode bridge, A power converter that converts a DC voltage output from the filter circuit into an arbitrary voltage and frequency, a motor driven by an AC voltage output from the power converter,
A compressor incorporated in the air conditioner incorporating the motor, and a power converter for driving the compressor.
An inverter control unit that sends out a pulse for WM control and sends out a pulse only to a certain phase of the upper arm when the compressor is stopped; and an inverter control unit that detects the voltage of the DC unit that is the output of the filter unit and A DC section voltage detector for outputting to an insulation resistance deterioration judging section, a current detector for detecting a motor current flowing through the motor and outputting it to the inverter control section and the insulation resistance deterioration judging section, and the DC section voltage detection when stopped. The insulation resistance is calculated from the output of the detector and the motor current detector, compared with a preset insulation resistance set value, and when the calculated insulation resistance is smaller than the set value, an alarm is output to notify the insulation deterioration. It comprises an insulation resistance deterioration judgment unit and an alarm unit for notifying the outside of the insulation resistance deterioration from the output of the insulation resistance deterioration judgment unit.

In the above configuration, high-frequency pulses are used as means for calculating insulation resistance, and actual measurement values are used as measurement information (DC voltage, frequency, and motor current). Highly accurate alarm can be issued.

According to a second aspect of the present invention, in the air conditioner, the compressor driving motor uses a power converter for converting an alternating current into a direct current and converting the obtained direct current into an alternating current. A three-phase AC power supply, a diode bridge that converts the three-phase AC voltage of the three-phase AC power supply to DC, a filter circuit that includes a reactor and an electrolytic capacitor and absorbs a ripple included in the diode bridge, and a filter output from the filter circuit. A power converter for converting a DC voltage into an arbitrary voltage and frequency, a motor driven by an AC voltage output from the power converter, and a compressor incorporated in the air conditioner including the motor, When the compressor is driven, a pulse for PWM control of the power converter is transmitted, and when the compressor is stopped, only the upper arm of one phase is turned on. An inverter control unit for sending a scan,
A current detector that detects a motor current flowing through the motor and outputs the detected current to the inverter control unit and the insulation resistance deterioration determination unit, and calculates an insulation resistance from a DC voltage set value and an output of the motor current detector when the motor is stopped. The insulation resistance deterioration judgment unit outputs an alarm that notifies the user of insulation deterioration when the insulation resistance calculated with respect to the set value is smaller than the set insulation resistance set value. On the other hand, it is constituted by an alarm unit for notifying the deterioration of the insulation resistance.

In the above configuration, a high-frequency pulse is used as a means for calculating the insulation resistance, and a preset value is used for the DC voltage among the measurement information (DC voltage, frequency and motor current). Although the accuracy is lower than that of the described invention, the cost is reduced because the DC voltage detector is not required.

According to a third aspect of the present invention, in the air conditioner, the compressor driving motor uses a power converter for converting AC to DC and converting the obtained DC to AC. A three-phase AC power supply, a diode bridge that converts the three-phase AC voltage of the three-phase AC power supply to DC, a filter circuit that includes a reactor and an electrolytic capacitor and absorbs a ripple included in the diode bridge, and a filter output from the filter circuit. A power converter for converting a DC voltage into an arbitrary voltage and frequency, a motor driven by an AC voltage output from the power converter, and a compressor incorporated in the air conditioner including the motor, During the operation of the compressor, a pulse for PWM control of the power converter is transmitted. An inverter control unit that outputs a DC voltage; a DC unit voltage detector that detects a voltage of the DC unit, which is an output of the filter unit, and outputs the voltage to the inverter control unit and the insulation resistance deterioration determination unit; and a motor current that flows through the motor. And a current detector for detecting and outputting to the inverter control unit and the insulation resistance deterioration determining unit, and an insulation resistance calculated from the outputs of the DC unit voltage detector and the motor current detector when the motor is stopped, and a set value held therein. Insulation resistance deterioration judgment unit that outputs an alarm that notifies insulation deterioration when the insulation resistance calculated with respect to the set value becomes smaller than the set value, and notifies the outside of the deterioration of insulation resistance from the output of the insulation resistance deterioration judgment unit And an alarm unit.

In the above configuration, the DC voltage may be output while the compressor is stopped. Therefore, even if the air conditioner is driven by an inverter using a low carrier frequency, for example, the carrier frequency is 3 kHz or less, the insulation resistance is not deteriorated. Diagnosis becomes possible. However, when compared with the invention described in claim 1 or 2 in which DC is used, accuracy is reduced.

[0018]

1 to 4 show an embodiment of the present invention.
This will be described with reference to FIG.

(Embodiment 1) FIG. 1 is a configuration diagram of an insulation deterioration detecting device of a compressor in an air conditioner according to Embodiment 1 of the present invention.

1 is a three-phase AC power supply, 2 is a diode bridge for converting three-phase AC to DC, 5 is a filter circuit comprising a reactor 3 and an electrolytic capacitor 4 for absorbing the ripple contained in the output of the diode bridge 2, and 6 is A power converter for converting a DC voltage output from the filter circuit into an arbitrary voltage and frequency, a compressor 7, a motor 8 driven by an AC voltage output from the power converter 6, and a power converter 6 An inverter control unit for transmitting a pulse for PWM control of the DC unit, a DC unit voltage detector for detecting the voltage of the DC unit and outputting it to the inverter control unit and the insulation resistance deterioration determination unit 12, and a motor unit for detecting the motor current and the inverter It is a current detector that outputs to the control unit 9 and the insulation resistance deterioration determination unit 12.

The insulation resistance deterioration judging section 12 calculates the insulation resistance from the outputs of the DC section voltage detector 10 and the motor current detector 11 at the time of stop, compares the insulation resistance with a preset insulation resistance set value, and compares the insulation resistance with the set value. When the calculated insulation resistance is reduced, an output is issued to an alarm unit 13 for notifying the insulation deterioration to the outside.

FIG. 2 shows the internal configuration of the power converter 6. This is a full bridge of a general IGBT.

In the operation of a normal air conditioner, P
Each phase is controlled by the WM control to drive the motor 8.

During operation, the transistors 1a, 1a,
1b, 2a, 2b, 3a, 3b are driven by pulses output from the inverter control unit 9, apply a pseudo sine wave voltage to the motor 8, and rotate the motor 8 at an arbitrary frequency and voltage. Since the PWM control of this motor is known, the description is omitted here.

In order to measure the deterioration of the insulation of the motor 8 when the motor 8 is stopped, the inverter control unit 9 controls a certain one of the upper arms of the transistors 1a, 2a and 3a, for example, a transistor 1a. A high-frequency pulse, for example, a pulse of 20 kHz or more is output.

When a pulsed high frequency voltage is applied to the motor, a leakage current flows. Here, when insulation deterioration is progressing in the target motor, a current corresponding to the insulation deterioration is added to the leakage current and flows in addition to the leakage current.

The insulation resistance deterioration judging section 12 calculates the insulation resistance from the motor current value measured by the motor current detector 11 and the DC section voltage value measured by the DC section voltage detector 10.

If the obtained insulation resistance is lower than the insulation resistance set value set to a certain value, an alarm unit 13 is output to the effect that the insulation resistance is reduced.

The alarm section 13 receives the output of the insulation resistance deterioration judging section 12 and notifies the outside of the occurrence of insulation resistance deterioration.

(Embodiment 2) FIG. 3 is a block diagram of a compressor insulation deterioration detecting device in an air conditioner according to Embodiment 2 of the present invention.

1 is a three-phase AC power supply, 2 is a diode bridge for converting three-phase AC to DC, 5 is a filter circuit for absorbing the ripple contained in the output of the diode bridge 2 including the reactor 3 and the electrolytic capacitor 4, and 6 is A power converter for converting a DC voltage output from the filter circuit into an arbitrary voltage and frequency, a compressor 7, a motor 8 driven by an AC voltage output from the power converter 6, and a power converter 6 An inverter control unit for transmitting a pulse for PWM control of the motor;
And a current detector for outputting to the insulation resistance deterioration determining unit 12.

The insulation resistance deterioration judging section 12 calculates the insulation resistance from the DC section voltage set value and the output of the motor current detector 11 at the time of stop, compares the insulation resistance with a preset insulation resistance set value, When the calculated insulation resistance is reduced, an output is issued to an alarm unit 13 for notifying the insulation deterioration to the outside.

The alarm section 13 receives the output of the insulation resistance deterioration determination section 12 and notifies the outside of the occurrence of insulation resistance deterioration.

In a normal operation of the air conditioner, P
Each phase is controlled by the WM control to drive the motor 8.

In order to measure the deterioration of the insulation of the motor 8 while the motor 8 is stopped, the inverter control unit applies a high-frequency signal to a specific one of the upper arms of the transistors 1a, 2a and 3a, for example, the transistor 1a. Pulse, for example, 2
Outputs a pulse of 0 kHz or more.

When a pulsed high frequency voltage is applied to the motor, a leakage current flows. Here, when insulation deterioration is progressing in the target motor, a current corresponding to the insulation deterioration is added to the leakage current and flows in addition to the leakage current.

The insulation resistance deterioration judging section 12 calculates the insulation resistance from the value of the motor current measured by the motor current detector 11 and a preset DC section voltage set value.

If the obtained insulation resistance is lower than a predetermined insulation resistance set value, the alarm unit 13 is output to the effect that the insulation resistance is reduced.

The alarm section 13 receives the output of the insulation resistance deterioration judging section 12 and notifies the outside of the occurrence of insulation resistance deterioration.

(Embodiment 3) FIG. 4 is a configuration diagram of a device for detecting insulation deterioration of a compressor in an air conditioner according to Embodiment 3 of the present invention.

1 is a three-phase AC power supply, 2 is a diode bridge for converting three-phase AC to DC, 5 is a filter circuit for absorbing the ripple contained in the output of the diode bridge 2 including the reactor 3 and the electrolytic capacitor 4, 6. Is a power converter for converting a DC voltage output from the filter circuit into an arbitrary voltage and frequency, 7 is a compressor, 8 is a motor driven by an AC voltage output from the power converter 6, and 14 is a compressor 7
While the compressor is in operation, it transmits a pulse for PWM control of the power converter 6, and when the compressor 7 is stopped, an inverter control unit that outputs a DC voltage from a certain one-phase upper arm, and 10 is a DC unit. A DC voltage detector 11 detects a voltage and outputs it to an inverter control unit and an insulation resistance deterioration determination unit 12. Reference numeral 11 denotes a current detector that detects a motor current and outputs it to the inverter control unit 14 and the insulation resistance deterioration determination unit 12.

The insulation resistance deterioration judging section 12 calculates the insulation resistance from the outputs of the DC section voltage detector 10 and the motor current detector 11 at the time of stoppage, compares the insulation resistance with a preset insulation resistance set value, and sets the set value. On the other hand, when the calculated insulation resistance becomes small, an output is issued to an alarm unit 13 for notifying the insulation deterioration to the outside.

The alarm unit 13 receives the output of the insulation resistance deterioration judgment unit 12 and notifies the outside of the occurrence of insulation resistance deterioration.

In the operation of a normal air conditioner, P
Each phase is controlled by the WM control to drive the motor 8.

During operation, the transistors 1a, 1a,
1b, 2a, 2b, 3a, 3b correspond to the inverter control unit 14
The motor 8 is driven by a pulse output from the controller 8 and a pseudo sine wave voltage is applied to the motor 8 to rotate the motor 8 at an arbitrary frequency and voltage. Since the PWM control of this motor is known, the description is omitted here.

In order to measure the deterioration of the insulation of the motor 8 while the motor 8 is stopped, the inverter control unit 14 controls a certain phase of the upper arm transistors 1a, 2a and 3a.
For example, for the transistor 1a, the transistor 1a
Is output. At this time, if insulation deterioration has progressed, current flows.

The insulation resistance deterioration judging section 12 calculates the value of the DC current flowing through the motor measured by the motor current detector 9 and the value of the DC section voltage measured by the DC section voltage detector 10,
Calculate the insulation resistance.

If the obtained insulation resistance is lower than the insulation resistance set value set to a certain value, the alarm unit 13 is output to the effect that the insulation resistance is reduced.

The alarm section 13 receives the output of the insulation resistance deterioration judging section 12 and notifies the outside of the occurrence of insulation resistance deterioration.

[0050]

As described above, according to the first aspect of the present invention, while the compressor is stopped, a high-frequency pulse is applied to the motor to measure the insulation resistance, so that the insulation deterioration is progressing. By detecting early and sending an alarm to the outside, repairs can be made without stopping the operation.

In addition, since a high-frequency pulse is used as a means for calculating the insulation resistance and an actual measurement value is used as measurement information (DC voltage, frequency and motor current), it is accurate. High alarm can be given.

According to the second aspect of the present invention, a high-frequency pulse is applied to the motor while the compressor is stopped, and the insulation resistance is measured. By sending an alarm to the customer, repairs can be made without stopping the operation.

Further, a high-frequency pulse is used as a means for calculating the insulation resistance, and a preset value is used for the DC voltage among the measurement information (DC voltage, frequency and motor current). Although the accuracy is reduced with respect to the invention, the cost is reduced because the DC voltage detector is not required.

According to the third aspect of the present invention, since a DC voltage may be output while the compressor is stopped, an air conditioner driven by an inverter using a low carrier frequency, for example, a carrier frequency of 3 kHz or less. Also, it is possible to diagnose the deterioration of the insulation resistance. However, when compared with the invention described in claim 1 and the invention described in claim 2, the accuracy is reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an insulation deterioration detection device for a compressor in an air conditioner according to Embodiment 1 of the present invention.

FIG. 2 is an internal configuration diagram of a power converter used for an insulation deterioration device of a compressor in the air conditioner of the embodiment.

FIG. 3 is a configuration diagram of a device for detecting insulation deterioration of a compressor in an air-conditioning apparatus according to Embodiment 2 of the present invention.

FIG. 4 is a configuration diagram of a device for detecting insulation deterioration of a compressor in an air-conditioning apparatus according to Embodiment 3 of the present invention.

FIG. 5 is a schematic configuration diagram showing a conventional insulation fault detection method.

FIG. 6 is a schematic configuration diagram of a measuring instrument used for insulation diagnosis.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Three-phase AC power supply 2 Diode bridge 3 Reactor 4 Electrolytic capacitor 5 Filter circuit 6 Power converter 7 Compressor 8 Motor 9 Inverter control part A 10 DC part voltage detection part 11 Current detector 12 Insulation resistance deterioration judgment part 13 Alarm part 14 Inverter control unit B

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G014 AA17 AB01 AB07 AC15 2G016 BA03 BB03 BC02 BD06 BD09 BD14 5H611 AA01 BB01 PP01 QQ05 QQ07

Claims (3)

[Claims] A compressor driving motor in an air conditioner uses a power converter for converting an alternating current into a direct current and converting the obtained direct current into an alternating current. A diode bridge that converts a three-phase AC voltage of an AC power supply into DC, a filter circuit that includes a reactor and an electrolytic capacitor and absorbs a ripple included in the diode bridge, and converts a DC voltage output from the filter circuit into an arbitrary voltage and frequency. A motor driven by an AC voltage output from the power converter, a compressor incorporated in the air conditioner incorporating the motor, and the power when the compressor is driven. Inverter control unit that sends out pulses for PWM control of the converter and sends out pulses only in a certain one-phase upper arm when the compressor is stopped A DC unit voltage detector that detects a voltage of a DC unit that is an output of the filter unit and outputs the voltage to the inverter control unit and an insulation resistance deterioration determination unit; and the inverter control unit that detects a motor current that flows through the motor. A current detector that outputs to the insulation resistance deterioration determination unit,
At the time of stop, the insulation resistance is calculated from the outputs of the DC section voltage detector and the motor current detector, and compared with a preset insulation resistance set value. A compressor insulation in an air conditioner, comprising: an insulation resistance deterioration determination unit that outputs an alarm indicating deterioration; and an alarm unit that notifies the outside of insulation resistance deterioration from an output of the insulation resistance deterioration determination unit. Deterioration detection device. 2. An air conditioner in which a compressor driving motor uses a power converter for converting an alternating current into a direct current and converting the obtained direct current into an alternating current. A diode bridge that converts a three-phase AC voltage of an AC power supply into DC, a filter circuit that includes a reactor and an electrolytic capacitor and absorbs a ripple included in the diode bridge, and converts a DC voltage output from the filter circuit to an arbitrary voltage and frequency. A motor driven by an AC voltage output from the power converter, a compressor incorporated in the air conditioner incorporating the motor, and the power when the compressor is driven. Inverter control unit that sends out a pulse for PWM control of the converter and sends out only one phase of the upper arm when the compressor is stopped And a current detector that detects a motor current flowing through the motor and outputs the detected current to the inverter control unit and the insulation resistance deterioration determination unit, and calculates an insulation resistance from a DC voltage set value and an output of the motor current detector when stopped. Compared with a preset insulation resistance set value, an insulation resistance deterioration determination unit that outputs an alarm indicating insulation deterioration when the insulation resistance calculated with respect to the set value decreases, and an output of the insulation resistance deterioration determination unit. An apparatus for detecting insulation deterioration of a compressor in an air conditioner, comprising: an alarm unit that notifies the outside of deterioration of insulation resistance. 3. A three-phase AC power source and said three-phase AC power supply, wherein a compressor driving motor in an air conditioner uses a power converter for converting AC to DC and converting obtained DC to AC. A diode bridge that converts a three-phase AC voltage of an AC power supply into DC, a filter circuit that includes a reactor and an electrolytic capacitor and absorbs a ripple included in the diode bridge, and converts a DC voltage output from the filter circuit to an arbitrary voltage and frequency. A motor driven by an AC voltage output from the power converter, a compressor incorporated in the air conditioner incorporating the motor, and the power converter during operation of the compressor. Inverter control that sends a pulse for PWM control of a compressor and outputs a DC voltage from the upper arm of one phase when the compressor is stopped A DC section voltage detector that detects a voltage of a DC section that is an output of the filter section and outputs the voltage to an inverter control section and an insulation resistance deterioration determination section; and a motor current that flows through the motor to detect the inverter current. Unit and the current detector to output to the insulation resistance deterioration determination unit, and when stopped, calculates the insulation resistance from the output of the DC unit voltage detector and the motor current detector, compares it with the set value internally, and sets the set value. An insulation resistance deterioration determination unit that outputs an alarm that notifies insulation deterioration when the insulation resistance calculated for the insulation resistance becomes small, and an alarm unit that notifies the outside of insulation resistance deterioration from the output of the insulation resistance deterioration determination unit A device for detecting insulation deterioration of a compressor in an air conditioner, characterized in that: