JP5467063B2 - Abnormality detection device and abnormality detection method for generator motor - Google Patents

Description

  The present invention relates to an abnormality detection device and an abnormality detection method for a generator motor that is driven by controlling electric power supplied from a DC power supply with an inverter and that regenerates electric power during braking.

In an electric vehicle driven by an electric motor using a DC power source, a failure of the generator motor becomes the biggest problem of the reliability of the electric vehicle.
The generator motor controls the speed of the electric vehicle by controlling the rotation speed of the generator motor by inverter control during driving, and decelerates the speed of the electric vehicle while regenerating power using the generator motor as a generator during braking. Yes.
Thus, the generator motor is the most important component device in an electric vehicle, and it is particularly important to ensure its reliability. The largest cause of failure of the generator motor is an insulation abnormality.

2. Description of the Related Art Conventionally, an insulation deterioration detection device for an inverter device that detects insulation deterioration of a load in a device using an inverter control power source is known. (For example, see Patent Document 1)
The apparatus of Patent Document 1 is configured such that a zero-phase current transformer, a low-pass filter, and an amplifier are integrated in a load circuit of a motor driven by an inverter output, and is installed on the load side of the inverter control circuit. The output of the amplifier is monitored by an insulation deterioration detection unit to detect insulation deterioration.
In addition, in an in-vehicle electric motor control device, there is known a device that detects and self-diagnose a significant decrease in performance when viewed as an automobile system resulting from deterioration of individual components. (For example, see Patent Document 2)
In the apparatus of Patent Document 2, the deterioration determination of the component parts is performed. For example, the deterioration determination of the current detector includes a current detector that detects the current amount of the AC motor, a deterioration determination unit, and an abnormality detection unit. Is doing.

Japanese Patent Laying-Open No. 2006-20483 (paragraph [0024], FIG. 8) JP 2007-60866 A (paragraphs [0021], [0045])

In the device of Patent Document 1, the leakage current that flows due to the insulation deterioration of the load is supplied from the ground resistance of the AC power supply, so it matches the power supply frequency, and the insulation deterioration detection unit corresponding to the power supply frequency is applied. There is a problem that it cannot be applied to an electric motor that is driven by controlling electric power supplied from a DC power supply with an inverter.
In particular, in the case of an electric motor operating at a normal commercial frequency, if the insulation is sound, the three-phase combined current is zero and no current flows on the secondary side of the zero-phase current transformer. However, when an insulation deterioration occurs in any phase and a ground current flows, the phase balance is lost and a current flows on the secondary side. At this time, in the case of an insulation abnormality in which the drive current of the electric motor is 20 to 30 A but the ground insulation resistance is reduced to about 0.5 MΩ, the flowing zero-phase current is a very small value of about 1 to 3 mA. . In such a state, when the frequency of the drive current 20 to 30A constantly fluctuates, a pulsating current flows to the secondary side of the zero-phase current transformer due to the influence of the frequency change, and the detection accuracy of the leakage current due to the insulation abnormality is improved. There was a problem that the insulation deteriorated and could not be detected.

  Moreover, the abnormality detection of the apparatus of patent document 2 is a deterioration detection of components including a current detector, and there existed a problem that abnormality of a generator motor could not be detected.

  Furthermore, in the generator motor, there is drive for driving and power regeneration for deceleration, and the rotation speed of the motor is constantly changing. For this reason, the frequency of the current flowing through the motor drive bus is constantly changing. Under such operating conditions, the conventional apparatus of prior art document 1 or prior art document 2 has a problem that abnormality detection of the generator motor cannot be performed.

  The present invention has been made to solve the above-described problems, and has an object to detect an insulation abnormality by obtaining an insulation resistance of a generator motor when the generator motor is driven and during power regeneration. To do.

  An abnormality detection device for a generator motor according to the present invention includes: a zero-phase current detection unit that detects a zero-phase current of a motor drive bus of the generator motor; a frequency detection unit that detects a frequency of a current flowing through the motor drive bus; Insulation resistance from the voltage detection means for detecting the voltage of the motor, the synchronous detection means for synchronously detecting the zero-phase current of the motor drive bus at the frequency of the generator motor, and the leakage current value output from the synchronous detection means and the voltage of the DC power supply And an abnormality detection means for detecting an abnormality by calculating.

  The abnormality detection method for a generator motor according to the present invention includes a zero-phase current detection step for detecting a zero-phase current of a motor drive bus of the generator motor, a voltage detection step for detecting a voltage of a DC power source, and a current flowing through the motor drive bus. Insulation resistance from the frequency detection step for detecting the frequency of the motor, the synchronous detection step for synchronously detecting the zero-phase current of the motor drive bus at the frequency of the generator motor, the leakage current value obtained in the synchronous detection step and the voltage of the DC power supply And an abnormality detection step for detecting an abnormality.

  An abnormality detection device for a generator motor according to the present invention includes: a zero-phase current detection unit that detects a zero-phase current of a motor drive bus of the generator motor; a frequency detection unit that detects a frequency of a current flowing through the motor drive bus; Insulation resistance from the voltage detection means for detecting the voltage of the motor, the synchronous detection means for synchronously detecting the zero-phase current of the motor drive bus at the frequency of the generator motor, and the leakage current value output from the synchronous detection means and the voltage of the DC power supply Therefore, when the generator motor is driven and during power regeneration, the influence of fluctuations in the rotational speed of the generator motor is removed, and the insulation resistance is increased with high accuracy. It is possible to calculate and detect an insulation abnormality.

  The abnormality detection method for a generator motor according to the present invention includes a zero-phase current detection step for detecting a zero-phase current of a motor drive bus of the generator motor, a voltage detection step for detecting a voltage of a DC power source, and a current flowing through the motor drive bus. Insulation resistance from the frequency detection step for detecting the frequency of the motor, the synchronous detection step for synchronously detecting the zero-phase current of the motor drive bus at the frequency of the generator motor, the leakage current value obtained in the synchronous detection step and the voltage of the DC power supply And an abnormality detection step for detecting an abnormality to eliminate the influence of fluctuations in the number of revolutions of the generator motor when the generator motor is driven and during power regeneration. It is possible to calculate and detect an insulation abnormality.

BRIEF DESCRIPTION OF THE DRAWINGS It is a system block diagram which concerns on the abnormality detection apparatus of the generator motor of Embodiment 1 of this invention. It is function explanatory drawing which concerns on the abnormality detection apparatus of the generator motor of Embodiment 1 of this invention. It is function explanatory drawing which concerns on the abnormality detection apparatus of the generator motor of Embodiment 1 of this invention. It is a system block diagram which concerns on the abnormality detection apparatus of the generator motor of Embodiment 2 of this invention. It is function explanatory drawing which concerns on the abnormality detection apparatus of the generator motor of Embodiment 2 of this invention. It is a system block diagram which concerns on the abnormality detection apparatus of the generator motor of Embodiment 3 of this invention. It is a system block diagram which concerns on the abnormality detection apparatus of the generator motor of Embodiment 4 of this invention. It is a flowchart which concerns on the abnormality detection method of the generator motor of Embodiment 5 of this invention.

Embodiment 1 FIG.
In the first embodiment, the zero-phase current of the motor drive bus is synchronously detected at the frequency of the current of the motor drive bus, the leakage current value is obtained, the insulation resistance is calculated using this leakage current value, and the generator motor The present invention relates to an abnormality detection apparatus for a generator motor according to the present invention for detecting an abnormality. In the first embodiment, a case where a vehicle motor is used as the generator motor will be described.
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a system configuration diagram relating to a generator motor abnormality detection device, and FIGS.

First, the system configuration of the abnormality detection device for a generator motor according to Embodiment 1 of the present invention will be described.
FIG. 1 shows a system configuration of an abnormality detection apparatus 1 for a generator motor according to Embodiment 1 of the present invention. The generator motor abnormality detection device 1 is roughly divided into three main parts: a motor drive unit, a motor control unit, and an abnormality detection unit.

The motor drive unit includes a generator motor 2, an inverter 3 that drives the generator motor 2 via a motor drive bus 6, a DC power source 4 that supplies power to the inverter 3, and a smoothing connected in parallel to the DC power source. Consists of a capacitor 5.
Here, the inverter 3 is composed of a switching element 21a made of IGBT or the like and a diode 21b connected in parallel with the switching element 21a. The generator motor 2 is grounded via a grounding wire 10.

  The motor control unit includes a controller 9 that outputs a PWM control signal to the inverter 3 that drives the generator motor 2, and a control device 8 that outputs a control signal according to the driving situation of the electric vehicle to the controller 9. Is done.

Next, the abnormality detection unit detects the zero-phase current transformer 12 that detects the zero-phase current flowing in the motor drive bus 6, the voltage detection circuit 14 that detects the voltage of the DC power supply 4, and the rotational speed of the generator motor 2. It is comprised from the rotation speed detector 15 and the abnormality detection circuit part 7 which detects the insulation abnormality of the generator motor 2 using the detection signal of these detectors.
The abnormality detection circuit unit 7 includes a synchronous detection circuit 13 that synchronously detects the current detected by the zero-phase current transformer 12, and an inverter 3 that drives the generator motor 2 from the rotational speed of the generator motor 2 detected by the rotational speed detector 15. It comprises a partial circuit of the controller 9 that calculates the frequency to be detected, an abnormality detection circuit 11 that detects an abnormality of the generator motor 2, and a display device 16 that displays the abnormality detection result.
The abnormality detection circuit 11 detects the insulation abnormality of the generator motor 2 by calculating the insulation resistance of the generator motor 2 using the output of the synchronous detection circuit 13 and the output of the voltage detection circuit 14 and comparing it with a reference value.
Further, a signal line is provided between the controller 9 and the abnormality detection circuit 11 for a signal for determining whether or not the abnormality detection of the generator motor 2 is performed depending on the driving state of the electric vehicle.

Here, the correspondence between each means that represents the configuration of the abnormality detection device 1 for a generator motor according to the first embodiment in terms of functions and the specific components and circuits in FIG. 1 is as follows.
The zero-phase current detection means corresponds to the zero-phase current transformer 12, and the frequency detection means corresponds to the rotation speed detector 15 and a partial circuit of the controller 9 for calculating the frequency. The voltage detection means corresponds to the voltage detection circuit 14, the synchronous detection means corresponds to the synchronous detection circuit 13, and the abnormality detection means corresponds to the abnormality detection circuit 11.

As the rotation speed detector 15, the number of times of the generator motor 2 can be measured by using, for example, an encoder.
As the display device 16, for example, an LED display or a liquid crystal display can be used.

  Next, functions and operations of the generator motor abnormality detection device 1 according to Embodiment 1 of the present invention will be described with reference to the system configuration diagram of FIG. 1 and the function explanatory diagrams of FIGS.

About the driving | running state of an electric vehicle, it can divide at the time of a drive, the time of electric power regeneration, and coasting. First, functions and operations during driving of the generator motor 2 will be described.
At the time of driving, the inverter 3 is driven by the voltage of the DC power supply 4, and the inverter 3 drives the generator motor 2. In controlling the speed of the electric vehicle during driving, the controller 9 controls the inverter 3 based on a signal from the control device 8 to control the rotation speed of the generator motor 2 by changing the frequency flowing through the motor drive bus 6. Is done. At the same time, the rotational speed detected by the rotational speed detector 15 is fed back to the controller 9 to control the speed of the electric vehicle, that is, the rotational speed of the generator motor 2. In this state, a zero phase current flowing in the motor drive bus 6 is detected by a zero phase current transformer 12 installed in the motor drive bus 6.

In the case of an electric motor operating at a normal commercial frequency, if the insulation is sound, the three-phase composite current is zero and no current flows on the secondary side of the zero-phase current transformer. However, when insulation deterioration occurs in any of the phases and a leakage current to the ground flows, the phase balance is lost and a current flows to the secondary side of the zero-phase current transformer. This leakage current is measured and the soundness of insulation is monitored.
However, since the speed of the generator motor 2 is constantly changing according to the speed, the frequency of the current flowing through the motor drive bus 6 constantly changes.

FIG. 2 shows the relationship between the rotational speed of the generator motor 2 and the drive current A from the start of traveling to a constant speed. As shown in FIG. 2, the driving current A during traveling is maximum when driving is started. As the speed of the electric vehicle increases, the driving torque of the generator motor 2 decreases, so the driving current A gradually decreases. The rotational speed of the generator motor 2 at this time is related to the frequency of the current flowing through the motor drive bus 6.
If further acceleration is applied to the curve of the drive current A in FIG. 2, the rotational speed of the generator motor 2 further changes according to the acceleration.

  As described above, since the frequency of the current flowing through the motor drive bus 6 constantly changes, the pulsating current flows on the secondary side of the zero-phase current transformer 12 due to the change in the frequency. It cannot be measured. Thus, the zero-phase current from the zero-phase current transformer 12 is synchronously detected by the synchronous detection circuit 13 using the frequency of the current flowing through the motor drive bus 6.

Next, the synchronous detection method will be described.
In order to accurately measure the zero-phase current, the rotation speed of the generator motor 2 is detected using the rotation speed detector 15, and the frequency of the current flowing through the motor drive bus 6 is determined by the controller 9 from the rotation speed.
In general, since the relationship between the rotational speed, the number of poles, and the frequency is expressed by equation (1), the rotational speed of the rotor of the generator motor 2 detected by the rotational speed detector 15 and the number of poles of the generator motor 2 are The frequency is calculated from
Number of rotations = 120 x frequency / number of poles (1)

The synchronous detection circuit 13 synchronously detects the zero-phase current from the zero-phase current transformer 12 using the frequency obtained from the above equation (1).
This synchronous detection extracts only the frequency component of the current flowing through the motor drive bus 6 from the current signal from the zero-phase current transformer 12. The signal detected by the zero-phase current transformer 12 is a current containing many frequency components, and in order to detect only the leakage current component of the motor drive current from this, detection is performed in synchronization with the frequency of the drive current. .

Basically, if synchronous detection is performed for one cycle, the influence of the change in the rotational speed can be eliminated to a practical level. However, synchronous detection is performed every several cycles in order to further improve the detection accuracy so that the current to be measured is minute and the initial stage of insulation deterioration can be detected.
Accordingly, synchronous detection of one measurement is performed for several cycles, specifically, every 3 to 5 cycles, and this synchronous detection is repeated. Thus, by repeating synchronous detection every several cycles, it is possible to eliminate the influence of the change in the rotational speed of the generator motor 2, that is, the change in the frequency of the current flowing through the motor drive bus 6, and to detect the leakage current with high sensitivity. it can.

The abnormality detection circuit 11 calculates an insulation resistance value from the leakage current value obtained by synchronous detection by the synchronous detection circuit 13 and the voltage detected by the voltage detection circuit 14, and determines whether it is normal or abnormal.
As a criterion for determining whether the insulation resistance of the generator motor 2 is normal or abnormal, the technical standards of the Japan Electrical Engineers Association can be used.
For example, the insulation resistance value of a low piezoelectric path having a ground voltage exceeding 150V and not more than 300V is defined as 0.4 MΩ or more.
Therefore, for example, 0.5 MΩ in consideration of the safety factor can be set to 0.4 MΩ. When the insulation resistance value calculated by the abnormality detection circuit 11 falls below the reference value compared to the reference value 0.5 MΩ, it is determined that there is an abnormality, and this abnormality determination is continuously determined a specified number of times, for example, five times. Then, an abnormal display is performed on the display device 16.

In FIG. 2, the monitoring range of the insulation abnormality of the generator motor 2 during driving is shown. The driving speed monitoring range is higher than the motor speed indicated by the monitoring limit speed f1 during driving, which will be described below.
Since the zero-phase current transformer 12 detects a zero-phase current using an electromagnetic phenomenon, there is a limit of frequency response. A normal zero-phase current transformer responds without problems if it is 40 Hz or higher. Therefore, when a normal zero-phase current transformer is used, the rotational speed range of the generator motor 2 corresponding to a drive current frequency of 40 Hz or more flowing through the motor drive bus 6 is a monitoring range during driving. The monitoring limit rotational speed at the time of driving is f1 shown in FIG.

  The relationship between the frequency of the drive current flowing through the motor drive bus 6 and the number of revolutions of the generator motor 2 is also related to the number of poles of the generator motor 2, and is represented by the above equation (1). . If the 6-pole generator motor 2 is used, the rotation speed is about 800 revolutions per minute at 40 Hz. Since the final reduction ratio of the first speed including the differential gear of the electric vehicle is 16 or more, the abnormality of the generator motor 2 can be detected at a speed of 600 m / h with a wheel rotation length of 2 m or more and a wheel circumference length of 2 m. The monitoring range varies depending on the number of poles of the generator motor 2, the reduction ratio of the electric vehicle, the outer diameter of the vehicle, and the like. However, the generator motor 2 having eight or more poles is often used for a normal vehicle motor. Since many reduction ratios are 16 or more, the monitoring range does not become smaller than the vehicle speed described above.

  In addition, although the frequency response of the zero-phase current transformer 12 is 40 Hz or more, when a high-performance zero-phase current transformer is used, the limit of the frequency response is 40 Hz or less. In this case, the monitoring range is further widened in the low speed range.

Next, the power regeneration of the generator motor 2 will be described.
During power regeneration, the inverter 3 functions as a diode bridge full-wave rectifier circuit. At the time of power regeneration (braking) when the generator motor 2 is driven from the outside, the generator motor 2 operates as a generator, and a voltage is induced in an armature coil (not shown). When this induced voltage exceeds the voltage of the DC power supply 4, a charging current flows from the generator motor 2 side to the DC power supply 4 through the diode bridge full-wave rectifier circuit of the inverter 3.
In general, in a generator motor, the rotational speed [N] is determined by the voltage [Ve] applied to the motor winding and the current [i] applied to the winding, and this relationship can be expressed by equation (2).
Voltage [Ve] = √2 · π (N / 60) · p · α · ω · Φ + i · r (2)
Here, p is the number of poles of the motor, ω is the number of turns of the winding, α is the winding coefficient, Φ is the magnetic flux, i is the current, and r is the internal resistance of the winding.
The first term on the right side of Equation (2) indicates the induced voltage of the winding, and the second term indicates the voltage drop in the winding. In general, during power regeneration, even if the rotational speed is low, the second term can be ignored because the internal resistance of the winding is small and the current value is also small.

During this power regeneration, the zero-phase current transformer 12 detects the zero-phase current of the charging current flowing from the armature coil of the generator motor 2 through the motor drive bus 6. At the same time, the controller 9 calculates the frequency of the regenerative current using the equation (1) based on the signal from the rotation speed detector 15 as in the case of driving.
Using the frequency obtained above, the zero-phase current from the zero-phase current transformer 12 is synchronously detected by the synchronous detection circuit 13, and the leakage current is detected.
Next, the abnormality detection circuit 11 calculates an insulation resistance value from the leakage current value obtained by synchronous detection by the synchronous detection circuit 13 and the voltage detected by the voltage detection circuit 14 to detect abnormality of the generator motor 2.

  FIG. 3 shows the relationship between the rotational speed of the generator motor 2 and the charging current B during power regeneration, and the monitoring range during power regeneration. Since the power regeneration is during braking, the rotational speed of the generator motor 2 is not actively controlled. When the electric vehicle shifts from high-speed running to braking, a high induced voltage is generated when the generator motor 2 rotates at high speed, and a large charging current flows. However, the induced voltage decreases as the electric vehicle decelerates. At the number of rotations of the generator motor 2 where the induced voltage is the same as the voltage of the DC power supply 4, the charging current becomes zero, and at the number of rotations of the generator motor 2 below that, the charging current does not flow and power regeneration cannot be performed. This rotational speed is the monitoring limit rotational speed f2 during power regeneration.

  The monitoring limit rotational speed f2 of the generator motor 2 at which the charging current becomes 0 is related to the voltage of the DC power supply 4. In the case of the generator motor 2 having a DC power supply of 300 V and 6 poles, this monitoring limit rotational speed f2 corresponds to 1500 revolutions per minute for the generator motor 2, and even in the verified results, abnormality detection is performed up to 1500 revolutions per minute. I was able to.

Next, the inertial running time will be described.
During inertial running, since the induced voltage generated in the armature coil of the generator motor 2 is low, no current flows through the motor drive bus 6 and no zero-phase current is detected. Therefore, during coasting, the abnormality detection of the generator motor 2 is not performed by the determination logic in the abnormality detection circuit 11 using the operation state signal output from the controller 9 to the abnormality detection circuit 11.

  The occurrence and progress of insulation deterioration of the generator motor 2 often progresses over time due to contamination, moisture absorption, temperature, mechanical vibration, etc., and hardly progresses rapidly in several tens of seconds. Therefore, it is not necessary to perform synchronous detection continuously in real time, and there is a sudden change in the number of revolutions between 3 and 5 cycles during driving or power regeneration, that is, a sudden change in the frequency of the current flowing through the motor drive bus 6. In that case, the accuracy of the abnormality detection of the generator motor 2 can be improved by removing the data.

  In the first embodiment, the controller 9 obtains the frequency of the current flowing through the motor drive bus 6 using the equation (1) from the rotation speed detected by the rotation speed detector 15. It may be provided separately from the controller 9.

  In the first embodiment, the frequency of the current flowing through the electric motor drive bus 6 is obtained from the rotational speed detected by the rotational speed detector 15 using the formula (1). 3 may be configured to obtain the frequency of the current flowing through the electric motor drive bus 6 from a control signal for PWM-controlling 3.

  As described above, in the first embodiment, the zero-phase current of the motor drive bus 6 is synchronously detected at the frequency of the current of the motor drive bus 6 to obtain the leakage current value, and the leakage current value is used for insulation. In order to detect the abnormality of the generator motor 2 by calculating the resistance, the influence of fluctuations in the number of revolutions of the generator motor 2 is removed during driving and power regeneration, and the insulation resistance is calculated with high accuracy to eliminate the insulation abnormality. There is an effect that can be detected.

Embodiment 2. FIG.
In the second embodiment, the generator / motor 2 is reduced by reducing the monitoring limit rotational speed and expanding the power regeneration range to a low speed range during the power regenerative braking with respect to the abnormality detection device 1 for the generator motor of the first embodiment. The present invention relates to an abnormality detection device 31 for a generator motor that can expand the monitoring range of insulation abnormality. The detection of the insulation abnormality of the generator motor 2 during driving is the same as in the first embodiment.
A second embodiment of the present invention will be described with reference to FIGS. FIG. 4 is a system configuration diagram related to the abnormality detection device 31 of the generator motor, and FIG. 5 is a functional explanatory diagram.

First, the system configuration of the generator motor abnormality detection device 31 according to the second embodiment of the present invention will be described.
FIG. 4 shows a system configuration of the abnormality detector 31 for a generator motor according to Embodiment 2 of the present invention. In FIG. 4, the same or corresponding parts as those in FIG.
For the motor drive unit of the generator motor abnormality detection device 1 according to the first embodiment, the circuit is switched so that the DC / DC converter 32 that is a DC voltage conversion circuit and the DC / DC converter 32 are used during power regeneration. The first relay 33a, the second relay 33b, and the relay contacts 34 and 35, which are switching relay circuits, are added.
Here, although the 1st relay 33a and the 2nd relay 33b use a separate relay, you may comprise with the same relay.
Further, a control signal line from the controller 9 to the DC / DC converter 32 is added to the motor controller of the generator motor abnormality detection device 1.

  Next, the function and operation of the abnormality detector 31 for a generator motor according to Embodiment 2 of the present invention will be described with reference to the system configuration diagram of FIG. 4 and the function explanatory diagram of FIG.

When the generator motor 2 shifts from driving to power regeneration, the first relay 33a and the second relay 33b are operated, the relay contact 34 closed during driving is opened, and the relay contact 35 opened during driving is closed simultaneously.
The voltage induced in the armature coil of the generator motor 2 is input to the DC / DC converter 32 via the inverter 3 acting as a diode bridge full-wave rectifier circuit. At the same time, the output voltage subjected to full-wave rectification is detected by the voltage detection circuit 14, and this detection voltage is input to the controller 9 via the abnormality detection circuit 11.

The controller 9 controls the DC / DC converter 32 so that the voltage detected by the voltage detection circuit 14 becomes the voltage of the DC power supply 4.
In the DC / DC converter 32, the output DC voltage can be made higher than the input DC voltage. Therefore, even when the full-wave rectified DC voltage is lower than the voltage of the DC power supply 4, The power can be regenerated by converting the voltage to a higher voltage.

In the second embodiment, the operation of the zero-phase current transformer 12, the calculation of the frequency of the current flowing through the motor drive bus 6, and the synchronous detection method and operation in the synchronous detection circuit 13 are the same as those in the first embodiment.
The abnormality detection circuit 11 detects an abnormality of the generator motor 2 by calculating an insulation resistance value from the leakage current value obtained by synchronous detection by the synchronous detection circuit 13 and the voltage detected by the voltage detection circuit 14. The abnormality detection method for the generator motor 2 is the same as that in the first embodiment.

  FIG. 5 shows the relationship between the rotational speed of the generator motor 2 and the charging currents B and B ′ during power regeneration in the second embodiment. The solid line B of the charging current in FIG. 5 is the charging current in the configuration of the first embodiment, and the broken line is the increased charging current B ′. When the rotational speed of the generator motor 2 is high, the charging current does not change much. However, when the rotational speed of the generator motor 2 is low, the DC / DC converter 32 is used to convert the full-wave rectified DC voltage to a voltage higher than the DC voltage of the DC power supply 4 and continue power regeneration. can do. For this reason, the charging current can be increased like the charging current B ′ indicated by the broken line. Accordingly, the monitoring limit rotational speed f2 in the first embodiment is reduced to f2 ′, and the monitoring range during power regeneration is expanded to the low speed range.

In the second embodiment, the input voltage of the DC / DC converter 32 is detected by the voltage detection circuit 14. However, the calculation is performed by the equation (2) from the rotation speed of the generator motor 2 detected by the rotation speed detector 15. The induced voltage can also be used.
Further, the induced voltage calculated by the equation (2) is obtained from the voltage value detected by the voltage detection circuit 14 and the rotation speed of the generator motor 2 detected by the rotation speed detector 15, and both are compared and there is no difference. Can be confirmed. If both are in the normal range as judged from the operating state, but there is a difference, the input voltage can be determined based on the detection voltage superiority of the voltage detection circuit 14.

Furthermore, in the above-described second embodiment, the inverter 9 is not controlled from the controller 9 during the power regeneration, but simply acts as a diode bridge full-wave rectifier circuit. However, the inverter 9 can also be controlled from the controller 9. .
In this case, instead of obtaining the frequency of the current flowing through the motor drive bus 6 from the rotation speed detected by the rotation speed detector 15, the motor drive from the control signal for controlling the inverter 3 by the controller 9 even during power regeneration. It can be set as the structure which calculates | requires the frequency of the electric current which flows through the bus-line 6. FIG.

  As described above, in the second embodiment, as in the first embodiment, the influence of fluctuations in the rotational speed of the generator motor 2 is removed at the time of driving and power regeneration, and the insulation resistance is increased with high accuracy. In addition to the effect of calculating and detecting the insulation abnormality, it is possible to widen the monitoring range of the insulation abnormality of the generator motor 2 to the low speed region during power regeneration.

Embodiment 3 FIG.
The third embodiment is obtained by adding a configuration for full-wave rectification of a three-phase alternating current as a direct current power supply to the abnormality detection device 1 for the generator motor of the first embodiment.
The detection of the insulation abnormality of the generator motor 2 during driving and power regeneration is the same as in the first embodiment.
A system configuration of an abnormality detection device 41 for a generator motor will be described with reference to FIG. 6 for Embodiment 3 of the present invention. In FIG. 5, the same or corresponding parts as those in FIG.

  The system configuration of the generator motor abnormality detection device 41 is obtained by adding a three-phase AC power source 42 and a rectifier circuit 43 to the motor drive unit of the generator motor abnormality detection device 1 of the first embodiment.

In the third embodiment, the three-phase AC power source 42 is rectified by the rectifier circuit 43 and charged to the DC power source 4 during driving, and the generator motor 2 is driven under the control of the inverter 3.
Other operations during driving and power regeneration are the same as those in the first embodiment.

  As described above, the third embodiment removes the influence of fluctuations in the number of revolutions of the generator motor 2 at the time of driving and during power regeneration, as in the first embodiment, so that the insulation resistance can be increased with high accuracy. The effect of calculating and detecting an insulation abnormality can also be exhibited in the case of the generator motor 2 that constitutes a DC power source by full-wave rectifying three-phase AC.

Embodiment 4 FIG.
The fourth embodiment is configured such that the power regenerated during power regeneration is returned to the three-phase AC power source with respect to the abnormality detection device 41 for the generator motor of the third embodiment.
A system configuration of an abnormality detection device 51 for a generator motor will be described with reference to FIG. 7 for Embodiment 4 of the present invention. In FIG. 7, the same or corresponding parts as those in FIG.

  The system configuration of the generator motor abnormality detection device 51 is such that the second inverter 52 and the second inverter 52 are used during power regeneration with respect to the motor drive section of the generator motor abnormality detection device 41 of the third embodiment. A third relay 53 which is a switching relay circuit for switching circuits and relay contacts 54 and 55 of the third relay 53 are added. Further, a control signal line from the controller 9 to the second inverter 52 is added.

In the fourth embodiment, the three-phase AC power source 42 is rectified by the rectifier circuit 43 and charged to the DC power source 4 during driving, and the electric motor 2 is driven under the control of the inverter 3.
During power regeneration, the third relay 53 operates, the relay contact 54 that was closed during driving is opened, and at the same time, the relay contact 55 that was opened during driving is closed.
The voltage induced in the armature coil of the generator motor 2 is input to the second inverter 52 via the inverter 3 acting as a diode bridge full-wave rectifier circuit.
At the same time, the voltage signal detected by the voltage detection circuit 14 is input to the controller 9 via a signal line between the abnormality detection circuit 11 and the controller 9. The controller 9 controls the second inverter 52 based on the voltage detected by the voltage detection circuit 14 and converts the DC voltage on the input side of the second inverter 52 into a three-phase AC voltage.

  As described above, the detection of the insulation abnormality of the generator motor 2 during driving is the same as that of the third embodiment, but the detection of the insulation abnormality of the generator motor 2 during power regeneration has been described in the second embodiment. Thus, the monitoring range of the insulation abnormality of the generator motor 2 can be further widened to the low speed region during power regeneration.

  The abnormality detection device 51 for the generator motor according to the fourth embodiment is effective for power regeneration of the generator motor 2 when the regenerative power is large and the capacity of the DC power supply 4 is small, and is high even in the generator motor 2 having such a configuration. Abnormality of the generator motor 2 can be detected with sensitivity.

  As described above, in the fourth embodiment, even in the case of the generator motor 2 configured to return the regenerated power to the three-phase AC power supply, it is possible to detect an abnormality in the generator motor 2 during driving and during power regeneration. At the same time, the insulation abnormality monitoring range of the generator motor 2 can be widened to a lower speed range during power regeneration.

Embodiment 5 FIG.
In the fifth embodiment, the zero-phase current of the motor driving bus is synchronously detected at the frequency of the current of the motor driving bus, the leakage current value is obtained, the insulation resistance is calculated using this leakage current value, and the abnormality is detected. The present invention relates to an abnormality detection method for a generator motor according to the present invention.
Hereinafter, Embodiment 5 of the present invention will be described with reference to FIG. 8 which is a flowchart according to the abnormality detection method for a generator motor.
The generator motor 2, the inverter 3, the DC power supply 4, the smoothing capacitor 5, and the motor drive bus 6 that are the motor drive unit of the first embodiment will be described with reference to FIG. 1. The detector and detection circuit necessary for detecting an insulation abnormality of the generator motor 2 are also the zero-phase current transformer 12 and the voltage detection circuit 14 described in the system configuration diagram of FIG. 1 described in the first embodiment. This will be described using the rotation speed detector 15.

When the process is started (S1), first, the zero-phase current transformer 12 detects the zero-phase current flowing in the motor drive bus 6 in the zero-phase current detection step (S2).
Next, in the voltage detection step (S3), the voltage of the DC power supply 4 is detected by the voltage detection circuit 14.
Next, in the frequency detection step (S4), the rotational speed of the generator motor 2 is detected by the rotational speed detector 15, and the frequency is calculated from the rotational speed using the equation (1).
Next, in the synchronous detection step (S5), only the frequency component calculated in the frequency detection step (S4) is extracted from the current flowing through the motor drive bus 6 detected in the zero-phase current detection step (S2), and the leakage current is extracted. Find the value.
Next, in the abnormality detection step (S6), the insulation of the generator motor 2 is isolated from the leakage current value flowing through the motor drive bus 6 extracted in the synchronous detection step (S5) and the voltage of the DC power source 4 detected in the voltage detection step (S3). Calculate the resistance value. Furthermore, by comparing with the reference value of the insulation resistance, it is determined whether it is normal or abnormal, thereby detecting the abnormality of the generator motor 2 and terminating the process (S7).

  In order to eliminate the influence of the change in the rotational speed of the generator motor 2, that is, the change in the current frequency flowing through the motor drive bus 6, and to detect the leakage current with high sensitivity, one cycle of synchronous detection for several cycles, for example, 3 cycles When the process is performed every five cycles, the zero-phase current detection step (S2) to the synchronous detection step (S5) are repeated as many times as necessary.

As hardware for realizing the abnormality detection method of the generator motor according to the fifth embodiment, for example, in FIG. 1 which is a system configuration diagram of the first embodiment, it is preferable to use dedicated hardware in the abnormality detection circuit unit 7. A configuration may be considered in which a computer that includes an input / output circuit for voltage, current, and pulse signals is left, leaving a part that can simplify software processing.
A controller 9 that performs PWM control of the inverter 3 is a part that can simplify software processing if it is left as dedicated hardware.

  As described above, the abnormality detection method for the generator motor according to the fifth embodiment includes the zero-phase current detection step, the voltage detection step, the frequency detection step, the synchronous detection step, and the abnormality detection step. The phase current is synchronously detected at the frequency of the electric current of the motor drive bus 6 to obtain a leakage current value, and the insulation resistance is calculated using the leakage current value to detect an abnormality in the generator motor 2. During power regeneration, there is an effect that the influence of fluctuations in the rotational speed of the generator motor 2 can be removed, insulation resistance can be calculated with high accuracy, and an insulation abnormality can be detected.

1, 31, 41, 51 An abnormality detection device for a generator motor, 2 a generator motor,
3 Inverter, 4 DC power supply, 5 Smoothing capacitor, 6 Motor drive bus,
7 anomaly detection circuit, 8 controller, 9 controller, 10 ground wire,
11 Abnormality detection circuit, 12 Zero phase current transformer, 13 Synchronous detection circuit, 14 Voltage detection circuit,
15 rotation speed detector, 16 display device, 21a inverter switching element,
21b diode, 32 DC / DC converter, 33a first relay,
33b Second relay, 34, 35 relay contact, 42 three-phase AC power supply, 43 rectifier circuit, 52 second inverter, 53 third relay, 54, 55 relay contact.

Claims (7)

In an abnormality detection device for a generator motor that is driven by controlling electric power supplied from a DC power supply with an inverter,
Zero-phase current detection means for detecting a zero-phase current of the motor drive bus of the generator motor, frequency detection means for detecting the frequency of the current flowing through the motor drive bus, and voltage detection means for detecting the voltage of the DC power supply Insulation resistance is calculated from synchronous detection means for synchronously detecting the zero-phase current of the motor drive bus at the frequency of the generator motor, a leakage current value output from the synchronous detection means, and a voltage of the DC power source. An abnormality detection device for a generator motor comprising abnormality detection means for detecting abnormality. The frequency detection means calculates a frequency of a current flowing through the motor drive bus using the rotation speed of the generator motor and the number of poles of the generator motor obtained from a signal of a rotation speed detector provided in the generator motor. Item 1. An abnormality detection apparatus for a generator motor according to Item 1. The abnormality detection apparatus for a generator motor according to claim 1, wherein the frequency detection means calculates a frequency of a current flowing through the motor drive bus using a control signal for driving the inverter when the generator motor is driven. The frequency detection means calculates a frequency of a current flowing through the motor drive bus using a control signal for driving the inverter when the generator motor is driven, and controls the inverter during power regeneration of the generator motor. The abnormality detection apparatus of the generator motor of Claim 1 which calculates the frequency of the electric current which flows through the said motor drive bus | bath using the control signal to perform. A switching relay circuit and a DC voltage conversion circuit are added between the DC power source and the inverter, and the DC voltage conversion is performed on the regenerative DC voltage generated on the DC voltage side of the inverter during power regeneration of the generator motor. The abnormality detection device for a generator motor according to claim 1, wherein voltage is converted by a circuit and regenerative power generated by the generator motor is regenerated to the DC power source. A three-phase AC power supply for supplying power to the DC power supply and a rectifier circuit are added, and a switching relay circuit and a second inverter are added between the three-phase AC power supply and the inverter, so that the electric power of the generator motor At the time of regeneration, the regenerative DC voltage generated on the DC voltage side of the inverter is converted to three-phase AC by the second inverter, and the regenerative power generated by the generator motor is regenerated to the three-phase AC power source. The abnormality detection apparatus for a generator motor according to claim 1. In the abnormality detection method of the generator motor that drives by controlling the power supplied from the DC power supply with an inverter,
A zero-phase current detection step for detecting a zero-phase current of a motor drive bus of the generator motor;
A voltage detection step of detecting a voltage of the DC power supply;
A frequency detection step of detecting a frequency of a current flowing through the electric motor drive bus;
A synchronous detection step of synchronously detecting the zero-phase current of the motor-driven bus at the frequency of the generator motor;
An abnormality detection method for a generator motor comprising an abnormality detection step of calculating an insulation resistance from a leakage current value obtained in the synchronous detection step and a voltage of the DC power source and detecting an abnormality.

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