JP6438729B2 - Insulation performance diagnostic device and method of setting capacitance value of pseudo capacitor - Google Patents

Description

The present invention relates to a method of setting the capacitance value of the pseudo capacitor used in the insulation performance diagnostic apparatus and its insulation performance diagnostic apparatus for a vehicle ground isolation circuit.

  In an electric vehicle (EV), a hybrid vehicle (HEV), and the like, a battery having a high voltage and a large capacity is mounted for the purpose of driving a motor. In addition, in order to obtain a more stable driving force, many vehicles handle a higher voltage by combining a booster circuit with a high voltage battery. Since such a high-voltage battery ensures insulation against vehicle grounding from the viewpoint of ensuring safety, it is very important to detect a leakage occurring between the high-voltage battery and the vehicle ground.

  As an insulation performance diagnostic device, AC or pulse voltage is applied from the oscillator to the low voltage side node of the vehicle ground insulation circuit through the coupling capacitor, and the voltage drop due to the drop in ground insulation resistance of the node is detected through each filter. Thus, it has been proposed to determine whether the ground insulation resistance is in a leakage state (for example, Patent Document 1).

  In this insulation performance diagnostic device, the detection circuit system for ground insulation resistance can be DC-isolated from the ground insulation circuit for vehicles by a coupling capacitor, so that the output voltage detected by the detection circuit can be converted to the normal ground power supply voltage. Can be processed by a control unit that operates in the above-described manner, so that the circuit configuration can be simplified and the safety is excellent.

JP 2004-347372 A

  However, in the above-described insulation performance diagnostic device, the difficulty of detecting leakage increases depending on the configuration of the ground insulation resistance. For example, when a parasitic capacitor is added in parallel to the ground insulation resistance, the impedance of the parasitic capacitor decreases depending on the capacitance value of the parasitic capacitor and the frequency of the voltage, and as a result, the ground insulation resistance and the parasitic resistance are reduced. The composite impedance of the capacitor falls below the threshold value for determining whether the ground insulation resistance is in a leakage state, and erroneously determines that the ground insulation resistance is in a leakage state even though the ground insulation resistance is not in a leakage state. There was a problem.

  Parasitic capacitors parasitic between the vehicle ground insulation circuit and the vehicle grounding vary depending on the shape of the vehicle, the connection state of the high-voltage battery, etc. Further, with the advancement of functions such as electric vehicles and hybrid vehicles, electronic control (ECU) As the number of units) and various protection circuits increases, the parasitic capacitor inevitably increases, so this problem is serious.

The present invention solves the above-described problems, and provides an insulation performance diagnostic device that can determine whether or not the ground insulation resistance is in a leakage state without affecting the parasitic capacitor, and the insulation performance thereof and its object is to provide a method of setting the capacitance value of the pseudo capacitors for use in diagnostic devices.

In order to achieve the above object, according to the first aspect of the present invention, there is provided a ground insulation resistance circuit having a ground insulation resistance to which a parasitic capacitor is connected in parallel. In the insulation performance diagnosis apparatus for diagnosing insulation performance of the ground insulation resistance circuit, a coupling capacitor having one end connected to a first node where the ground insulation circuit for a vehicle and the ground insulation resistance circuit are commonly connected If, pseudo- first voltage dividing resistors having one end to a second node which is the other end of the coupling capacitor is connected, it is connected pseudo insulation resistance and pseudo capacitors parallel end connected to ground An insulation resistance circuit; a second voltage dividing resistor having one end connected to a third node which is the other end of the pseudo insulation resistance circuit; the other end of the first voltage dividing resistor and a second voltage dividing resistor On the other end of And an output circuit having an amplitude corresponding to the difference between the amplitude of the first signal voltage appearing at the second node and the amplitude of the second signal voltage appearing at the third node. When the magnitude of the amplitude of the output voltage of the detection circuit falls below a first determination threshold value, it is determined that the ground insulation resistance of the ground insulation resistance circuit is in a leakage state And a control unit having first determination means.

  The invention according to claim 2 is the insulation performance diagnosis device according to claim 1, wherein the resistance value of the pseudo insulation resistance of the pseudo insulation resistance circuit is such that the ground insulation resistance of the ground insulation resistance circuit is in a leakage state. Set to a resistance value smaller than the resistance value determined to be, the capacitance value of the pseudo capacitor of the pseudo insulation resistance circuit is set to be equivalent to the capacitance value of the parasitic capacitor of the ground insulation resistance circuit, It is characterized by that.

The invention according to claim 3 is the insulation performance diagnostic device according to claim 1 or 2,
The control unit is configured to detect the ground insulation resistance when a difference between a phase of the output voltage output from the detection circuit and a phase of the AC or pulse voltage output from the oscillation circuit is larger than a second determination threshold value. And a second determination unit that determines that the second determination unit is in a leakage state. The determination result obtained when the second determination unit is determined to be in a leakage state is determined by the first determination unit. It is characterized by giving priority over results.

  According to a fourth aspect of the present invention, in the insulation performance diagnostic device according to the first, second, or third aspect, the frequency component of the AC or pulse voltage inserted between the second node and the detection circuit. And a low-pass filter that is inserted between the detection circuit and the first determination unit of the control unit and that removes high-frequency components.

  According to a fifth aspect of the present invention, in the insulation performance diagnostic device according to the first, second, third, or fourth aspect, the control unit determines an amplitude of the AC or pulse voltage during a normal operation of the insulation performance diagnostic device. Voltage amplitude switching means for switching and outputting between the normal amplitude and the amplitude smaller than the normal amplitude for normal operation confirmation of the insulation performance diagnostic device.

  According to a sixth aspect of the present invention, in the insulation performance diagnostic device according to the first, second, third, or fourth aspect, the first control unit is controlled by the control unit when confirming normal operation of the insulation performance diagnostic device. A first test circuit configured to set the amplitude of the signal voltage to be equivalent to the amplitude when the ground insulation resistance of the ground insulation resistance circuit is assumed to be in a leakage state regardless of the impedance of the ground insulation resistance circuit; It is characterized by.

  According to a seventh aspect of the present invention, in the insulation performance diagnostic device according to the first, second, third, or fourth aspect, the second control unit is controlled by the control unit when a normal operation of the insulation performance diagnostic device is confirmed. A second test circuit is provided that makes the amplitude of the signal voltage higher than the amplitude during normal operation of the insulation performance diagnostic device.

Pseudo setting of the capacitor insulation performance diagnostic device of the invention according to claim 8, the resistance in parallel with the ground insulation resistance circuit insulation performance diagnostic apparatus according to any one of claims 1 to 7 is known of connecting a known resistance, the change of the capacitance value of the capacitor pseudo- pseudo insulation resistance circuit, the pseudo-capacitor capacitance value when the amplitude of the output voltage of the detecting circuit shown the lowest value by the change It is set to a capacitance value.

The invention according to claim 9, in pseudo setting of the capacitor insulation performance diagnostic apparatus according to claim 8, the resistance value of the known resistance, the same as the resistance value of the pseudo insulation resistance of the pseudo insulation resistance circuit A resistance value is set.

According to insulation performance diagnostic apparatus of the present invention, canceled by pseudo capacitors the influence of the parasitic capacitor is added in parallel to the ground insulation resistance of the ground insulation resistance circuit, connected in parallel with pseudo insulation resistance of the pseudo insulation resistance circuit Therefore, it is possible to determine whether or not the ground insulation resistance of the ground insulation resistance circuit is in a leakage state without being affected by the parasitic capacitor of the ground insulation resistance circuit.

Further, according to the pseudo setting of the capacitor insulation performance diagnostic apparatus of the present invention, the capacitance value of the pseudo capacitor pseudo insulation resistance circuit, to accurately set the capacitance value corresponding to the parasitic capacitor of the ground insulation resistance circuit Therefore, the parasitic capacitor can be canceled by the pseudo capacitor accurately, and the diagnosis by the insulation performance diagnostic device can be performed accurately.

It is a block diagram which shows the structure of the 1st Example of the insulation performance diagnostic apparatus of this invention. It is a detection characteristic figure of ground insulation resistance of an insulation performance diagnostic device of the present invention and a conventional example. It is a block diagram which shows the structure of the 2nd Example of the insulation performance diagnostic apparatus of this invention. It is a block diagram for explaining the pseudo capacitor configuration of a third embodiment of the insulation performance diagnostic apparatus of the present invention. It is a block diagram which shows the structure of the 4th Example of the insulation performance diagnostic apparatus of this invention. It is a block diagram which shows the structure of the 5th Example of the insulation performance diagnostic apparatus of this invention. It is a block diagram which shows the structure of the 6th Example of the insulation performance diagnostic apparatus of this invention. It is a block diagram which shows the structure of the 7th Example of the insulation performance diagnostic apparatus of this invention.

<First embodiment>
A first embodiment of the insulation performance diagnostic apparatus of the present invention will be described with reference to FIG. Reference numeral 10 denotes a ground isolation circuit for a vehicle that is insulated from the vehicle body (grounding) of the automobile. The ground-insulated high-voltage battery 11, a three-phase motor for travel (not shown), and a three-phase motor that controls the driving of the three-phase motor. It has a phase inverter circuit and the like, and constitutes a high voltage battery circuit system for electric vehicles and hybrid vehicles.

  Reference numeral 20 denotes a ground insulation resistance circuit connected to the node N1 of the negative terminal of the high voltage battery 11. The ground insulation resistance circuit 20 includes a ground insulation resistance R1, and a parasitic capacitor C1 connected in parallel is parasitic on the ground insulation resistance R1.

  A control unit 30 using a computer includes an oscillation circuit 31 and a processing unit (not shown). One end of the voltage dividing resistors R2 and R3 is connected to the output side of the oscillation circuit 31. A coupling capacitor C2 is connected between the node N2 at the other end of the voltage dividing resistor R2 and the node N1. The node N3 at the other end of the voltage dividing resistor R3 is connected to the pseudo insulation resistance circuit 40.

The pseudo insulation resistance circuit 40 includes a pseudo capacitor C3 connected in parallel to it a pseudo-insulation resistance R4. The resistance value of the pseudo-insulation resistance R4 is set to a value smaller than the value determined that the ground insulation resistance R1 is in a leakage state. The capacitance value of the pseudo capacitor C3 is set to be equivalent to the capacitance value of the parasitic capacitor C1.

  Reference numeral 50 denotes a detection circuit that generates a detection voltage V0 for determining whether the insulation resistance circuit 20 is insulated or not. The detection circuit 50 includes a differential amplifier 51, and the amplitude of the signal voltage V2 at the node N2 and the signal voltage V3 at the node N3. A difference in amplitude (= V2−V3) is detected and amplified to generate a detection voltage V0, which is sent to the control unit 30. The first signal voltage described in the claims is V2, and the second signal voltage is V3.

  The control unit 30 performs A / D conversion on the amplitude of the detection voltage V0 and captures it as an absolute value. And when the magnitude | size is less than the preset 1st determination threshold value, the 1st determination means which determines with the earth insulation resistance R1 of the earth insulation resistance circuit 20 being in an electric leakage state is provided.

  In the determination, the control unit 30 applies an alternating current or pulse voltage Vin of a predetermined frequency from the oscillation circuit 31 to the ground insulation resistance circuit from the node N1 via the voltage dividing resistor R2, the node N2, and the coupling capacitor C2. 20 applied. At the same time, the voltage is applied to the pseudo-insulation resistance circuit 40 via the voltage dividing resistor R3 and the node N3.

  At this time, the signal voltage V2 at the node N2 is a voltage obtained by dividing the voltage Vin applied from the oscillation circuit 31 by the impedance of the voltage dividing resistor R2, the coupling capacitor C2, and the ground insulation resistance circuit 20. The amplitude of the signal voltage V2 is substantially proportional to the resistance value of the ground insulation resistance R1.

  That is, the amplitude of the signal voltage V2 increases as the resistance value of the ground insulation resistance R1 increases, and decreases as it decreases. However, since the voltage Vin is an alternating current or pulse voltage, if the capacitance value of the parasitic capacitor C1 is large, the amplitude of the signal voltage V2 is small even if the resistance value of the ground insulation resistance R1 is large.

  On the other hand, the signal voltage V3 at the node N3 is a voltage obtained by dividing the voltage Vin applied from the oscillation circuit 31 by the impedance of the voltage dividing resistor R3 and the pseudo insulation resistance circuit 40. The amplitude of the voltage V3 is a fixed value.

  Here, as described above, the resistance value of the pseudo-insulation resistor R4 is set to a resistance value smaller than the value determined that the ground insulation resistance R1 is in a leakage state, and the capacitance value of the pseudo-capacitor C3 is equal to that of the parasitic capacitor C1. Since the capacitance value is set, the amplitude of the signal voltage V3 is a value corresponding to the leakage. On the other hand, the amplitude of the signal voltage V2 is sufficiently larger than the amplitude of the signal voltage V3 when the ground insulation resistance R1 has a normal resistance value, but the signal voltage V3 when the ground insulation resistance R1 is in a leakage state. Drops to a value close to the amplitude of. At this time, the influence of the capacitor C1 is almost canceled by the capacitor C3.

  The voltage amplification factor of the differential amplifier 51 of the detection circuit 50 is set to 6 to 40 dB, for example, 20 dB (100 times). Since the amplitude of the output voltage V0 of the detection circuit 50 is obtained by amplifying the difference (V2−V3) between the amplitude of the signal voltage V2 and the signal voltage V3, the amplitude becomes a voltage substantially proportional to the resistance value of the ground insulation resistance R1.

  The analog output voltage V0 input to the control unit 30 is converted into a digital signal by the control unit 30 and simultaneously converted to an absolute value. When the value of the digital signal is lower than the first determination threshold value, the first determination means determines that the ground insulation resistance R1 is in a leakage state.

  FIG. 2 shows a simulation result of the amplitude of the output voltage V0 that changes according to the change in the resistance value of the ground insulation resistance R1. It can be confirmed that the characteristic curve of the “present invention” is more sensitive to the change in the amplitude of the output voltage V0 relative to the change in the resistance value of the ground insulation resistance R1 than the characteristic curve of the “prior art”. It can be seen that the detection accuracy of the variation of the resistance value of the insulation resistance R1 is improved.

<Second embodiment>
A second embodiment of the insulation performance diagnostic apparatus of the present invention will be described with reference to FIG. In this embodiment, the difference φ between the phase φ1 of the voltage Vin output from the control unit 30 and the phase φ2 of the output voltage V0 of the detection circuit 50 is detected by the phase difference detection circuit 60 and input to the control unit 30. And in the control part 30, when the phase difference exceeds a 2nd determination threshold value, it determines with the ground insulation resistance R1 being in an electric leakage state.

  The amplitude of the output voltage V0 is a voltage having an amplitude corresponding to the difference between the amplitude of the signal voltage V2 and the amplitude of V3 (V2-V3) as described above, and the control unit 30 determines the absolute value of the amplitude of the output voltage V0. It is compared with a first determination threshold value. When the polarity of the amplitude of the output voltage V0 obtained by the calculation of the difference (V2-V3) is negative, the amplitude of the signal voltage V2 is greatly reduced, and the ground insulation resistance R1 is in a leakage state. In this case, if the absolute value of the amplitude of the output voltage V0 is smaller than the first determination threshold value, it is accurately determined that there is a leakage current, but is larger than the first determination threshold value. In such a case, it is erroneously determined that there is no leakage.

  Therefore, in this embodiment, the control unit 30 detects not only the amplitude of the output voltage V0 but also the difference between the phase φ1 of the voltage Vin output from the control unit 30 and the phase φ2 of the output voltage V0. When the resistance value of the ground insulation resistance R1 is extremely small, the influence of the parasitic capacitor C1 increases, and the phase φ2 of the output voltage V0 increases. Therefore, when the phase difference φ exceeds the preset second determination threshold value, the second determination means provided in the control unit 30 determines that the ground insulation resistance R1 is in a leakage. By including such second determination means, it is possible to prevent erroneous determination that there is no leakage when the resistance value of the ground insulation resistance R1 becomes extremely small. In addition, when it is determined that the leakage state is caused by the second determination threshold, the determination result that the leakage is not detected by the first determination threshold is cancelled. In other words, the result determined by the second determination threshold is prioritized.

<Third embodiment>
A third embodiment of the insulation performance diagnostic apparatus of the present invention will be described with reference to FIG. In this embodiment, the capacitance value of the parasitic capacitor C1 of the ground insulation resistance circuit 20 is calculated. The parasitic capacitor C1 shows different values depending on the shape of the vehicle, the connection state of the high voltage battery 11, and the like. Therefore, the known resistance R5 is connected in parallel to the ground insulation resistance circuit 20 after the vehicle is assembled. Then, the insulation performance diagnosis apparatus is operated to sequentially change the capacitance value of the pseudo capacitor C3 of the pseudo insulation resistance circuit 40, and the value of the parasitic capacitor C1 is obtained from the fluctuation of the amplitude of the output voltage V0 at that time.

  When the insulation performance diagnosis apparatus operates, an alternating current or pulse voltage Vin is applied to the node N2 through the voltage dividing resistor R2, and is applied to the node N3 through the voltage dividing resistor R3. The resistance value of the ground insulation resistance R1 at the beginning of vehicle assembly is considered to be very large. The signal voltage V2 at the node N2 is a voltage obtained by dividing the voltage Vin by the impedance of the voltage dividing resistor R2, the coupling capacitor C2, and the ground insulation resistance circuit 20, and is input to the differential amplifier 51 of the detection circuit 50. The signal voltage V3 at the node N3 is a voltage obtained by dividing the voltage Vin by the impedance of the voltage dividing resistor R3 and the pseudo insulation resistance circuit 40, and is input to the differential amplifier 51 of the detection circuit 50. The differential amplifier circuit 51 amplifies the difference between the amplitudes of the signal voltages V 2 and V 3 and outputs the output voltage V 0 to the control unit 30.

  Here, the voltage dividing resistors R2 and R3 are set to the same resistance value, the resistance value of the known resistor R5 is set to be the same as the resistance value of the pseudo-insulation resistor R4, and the capacitance value of the coupling capacitor C2 is sufficiently small in impedance. Set as follows. At this time, the resistance value of the ground insulation resistance R1 is very large and does not affect the output voltage V0.

Thus, the output voltage V0 becomes a voltage corresponding to the voltage comparing the impedance of the capacitor C3 pseudo- parasitic capacitor C1. Therefore, the output voltage V0 when the capacitance value of the pseudo capacitor C3 becomes equal to the capacitance value of the parasitic capacitor C1 is minimized.

Therefore, the amplitude of the output voltage V0 is measured while gradually increasing the capacitance value of the pseudo capacitor C3 from a value (for example, 0f) sufficiently smaller than the assumed capacitance value of the parasitic capacitor C1. At this time, the amplitude of the output voltage V0 decreases when the capacitance value of the pseudo capacitor C3 approaches the capacitance value of the parasitic capacitor C1, and the amplitude of the output voltage V0 increases when it moves away from the capacitance value of the parasitic capacitor C1. Therefore, the capacitance value of the pseudo capacitor C3 at which the amplitude is the smallest of the output voltage V0, it is possible to determine the capacitance value of the parasitic capacitor C1. From the above, if the capacitance value of the pseudo capacitor C3 is set to the capacitance value, the influence of the parasitic capacitor C1 can be canceled accurately.

<Fourth embodiment>
A fourth embodiment of the insulation performance diagnostic apparatus of the present invention will be described with reference to FIG. In this embodiment, a band pass filter circuit 70 is connected between the node N 2 and the detection circuit 50, and a low pass filter circuit 80 is connected between the detection circuit 50 and the control unit 30.

  The bandpass filter circuit 70 extracts a narrowband component including the basic component of the voltage Vin from the oscillation circuit 31 from the signal voltage V2 at the node N2, and inputs the extracted narrowband component to the detection circuit 50. The low-pass filter circuit 80 removes the high-frequency noise component of the output voltage V0 output from the detection circuit 50 and causes the control unit 30 to input it.

  From the above, in the present embodiment, the high voltage battery 11 of the vehicle ground insulation circuit 10 can remove noise generated during power supply such as motor drive.

<Fifth embodiment>
A fifth embodiment of the insulation performance diagnostic apparatus of the present invention will be described with reference to FIG. In this embodiment, since the control unit 30 confirms the operations of the oscillation circuit 31, the pseudo insulation resistance circuit 40, and the detection circuit 50, the resistance value of the ground insulation resistance R1 is reduced to a value indicating leakage during the operation confirmation period. When the voltage Vin ′ (Vin ′ <Vin) having a small amplitude such that an output voltage V0 having an amplitude equivalent to that obtained is obtained is divided by the voltage amplitude switching means (not shown) of the control unit 30, the voltage dividing resistors R3 and R2 And applied to the nodes N2 and N3.

  Thus, if the amplitude of the output voltage V0 input to the control unit 30 falls below the first determination threshold within the operation confirmation period of the control unit 30 that has output the voltage Vin ′, the oscillation circuit 31 and the pseudo insulation resistance It is determined that the circuit 40 and the detection circuit 50 are normal. However, when the amplitude of the output voltage V0 is larger than the first determination threshold value, it can be confirmed that the oscillation circuit 31, the pseudo insulation resistance circuit 49, and the detection circuit 50 are defective.

<Sixth embodiment>
A sixth embodiment of the insulation performance diagnostic apparatus of the present invention will be described with reference to FIG. In this embodiment, a first test circuit 90 controlled by the control unit 30 is provided. The first test circuit 90 includes a grounded emitter type transistor Q1 that operates as a circuit operation switch, and a voltage dividing resistor R6 that connects the collector of the transistor Q1 and the node N2.

  The control unit 30 turns on the transistor Q1 of the first test circuit 90 for a predetermined short period in order to confirm the operations of the bandpass filter circuit 70, the detection circuit 50, and the low-pass filter 70. As a result, the signal voltage V2 is a voltage in which the amplitude of the voltage Vin is reduced in accordance with the voltage dividing resistance ratio of the voltage dividing resistors R2 and R6, and is input to the detection circuit 50. The signal is output to the control unit 30 through the circuit 50 and the low-pass filter circuit 80.

  However, the voltage dividing ratio of the voltage dividing resistors R2 and R6 is set so that the amplitude of the output voltage V0 input to the control unit 30 is smaller than the first determination threshold value.

  In this way, the first test circuit 90 sets the signal voltage V2 to the voltage when the leakage occurs, and the signal voltage V3 is a fixed voltage. If it is determined that it is in a state, it can be confirmed that the bandpass filter circuit 70, the detection circuit 50, and the lowpass filter circuit 80 are operating normally.

<Seventh embodiment>
A seventh embodiment of the insulation performance diagnostic apparatus of the present invention will be described with reference to FIG. In this embodiment, a second test circuit 100 including a grounded emitter type transistor Q2 whose on / off is controlled by the control unit 30 is provided. In the pseudo-insulation resistance circuit 40A, the resistor R7 is connected in series to the low voltage side of the pseudo-insulation resistor R4, and the resistor R7 is connected in series to the resistor R4 by turning off the transistor Q2.

  The transistor Q2 of the second test circuit 100 is turned on by the control unit 30 during normal operation. However, when the operations of the bandpass filter circuit 70, the detection circuit 50, and the low-pass filter 70 are confirmed, the control unit 30 turns off the transistor Q2 for a predetermined short period. As a result, the combined impedance of the pseudo insulation resistance circuit 40A increases, and the signal voltage V3 increases.

  The signal voltage V3 is input to the control unit 30 through the detection circuit 50 and the low-pass filter circuit 80. However, the resistance value of the resistor R7 is such that the amplitude of the output voltage V0 input to the control unit 30 when the band-pass filter circuit 70, the detection circuit 50, and the low-pass filter circuit 80 are normal is the first determination threshold voltage. It is set to be smaller.

  In this way, if it is determined that the first determination circuit is in a leakage state, it can be confirmed that the bandpass filter circuit 70, the detection circuit 50, and the lowpass filter circuit 80 are operating normally.

10: vehicle ground isolation circuit, 11: high voltage battery 20: ground insulation resistance circuit 30: controller, 31: an oscillation circuit 40: pseudo insulation resistance circuit 50: detection circuit 60: a phase difference detection circuit 70: a band-pass filter Circuit 80: Low-pass filter circuit 90: First test circuit 100: Second test circuit

Claims (9)

Insulation performance diagnosis for diagnosing insulation performance of the ground insulation resistance circuit when the ground insulation resistance circuit having ground insulation resistance to which a parasitic capacitor is connected in parallel is insulated from the vehicle body as a ground. In the device
A coupling capacitor having one end connected to a first node to which the vehicle ground insulation circuit and the ground insulation resistance circuit are commonly connected;
A first voltage-dividing resistor having one end connected to a second node that is the other end of the coupling capacitor;
And insulation resistance circuit pseudo- capacitor and pseudo insulation resistance is one connected in parallel is connected to the ground pseudo-,
A second voltage dividing resistor having one end connected to a third node which is the other end of the pseudo-insulation resistance circuit;
An oscillation circuit for inputting an AC or pulse voltage to the other end of the first voltage dividing resistor and the other end of the second voltage dividing resistor;
A detection circuit for outputting an output voltage having an amplitude corresponding to a difference between an amplitude of the first signal voltage appearing at the second node and an amplitude of the second signal voltage appearing at the third node;
First determination means for determining that the ground insulation resistance of the ground insulation resistance circuit is in a leakage state when the magnitude of the amplitude of the output voltage of the detection circuit falls below a first determination threshold value. A control unit;
An insulation performance diagnostic apparatus comprising:
In the insulation performance diagnostic device according to claim 1,
The resistance value of the pseudo-insulation resistance of the pseudo-insulation resistance circuit is set to a resistance value smaller than a resistance value determined that the ground-insulation resistance of the ground-insulation resistance circuit is in a leakage state,
The capacitance value of the pseudo capacitor of the pseudo insulation resistance circuit is set to be equivalent to the capacitance value of the parasitic capacitor of the ground insulation resistance circuit.
Insulation performance diagnostic device characterized by that. In the insulation performance diagnostic device according to claim 1 or 2,
The control unit is configured to detect the ground insulation resistance when a difference between a phase of the output voltage output from the detection circuit and a phase of the AC or pulse voltage output from the oscillation circuit is larger than a second determination threshold value. And a second determination means for determining that is in an electric leakage state,
An insulation performance diagnostic apparatus according to claim 1, wherein the determination result when the second determination means is determined to be in a leakage state has priority over the determination result of the first determination means.
In the insulation performance diagnostic device according to claim 1, 2, or 3,
A band-pass filter circuit that is inserted between the second node and the detection circuit and that passes a frequency component of the AC or pulse voltage;
A low-pass filter inserted between the detection circuit and the first determination means of the control unit for removing high-frequency components;
An insulation performance diagnostic apparatus, further comprising: In the insulation performance diagnostic device according to claim 1, 2, 3, or 4,
The control unit sets the amplitude of the AC or pulse voltage to a normal amplitude during normal operation of the insulation performance diagnostic device and an amplitude smaller than the normal amplitude for confirming normal operation of the insulation performance diagnostic device. An insulation performance diagnostic device comprising voltage amplitude switching means for switching and outputting. In the insulation performance diagnostic device according to claim 1, 2, 3, or 4,
When the normal operation of the insulation performance diagnostic device is confirmed, the control unit controls the amplitude of the first signal voltage regardless of the impedance of the ground insulation resistance circuit, and the ground insulation of the ground insulation resistance circuit. An insulation performance diagnostic apparatus, comprising: a first test circuit that is set to have an amplitude equivalent to that when a resistor is in a leakage state. In the insulation performance diagnostic device according to claim 1, 2, 3, or 4,
A second test circuit configured to make the amplitude of the second signal voltage higher than the amplitude during normal operation of the insulation performance diagnostic device by being controlled by the control unit when confirming normal operation of the insulation performance diagnostic device; An insulation performance diagnostic apparatus comprising: Connect resistance parallel with the ground insulation resistance circuit insulation performance diagnostic apparatus according to any one of claims 1 to 7 the known known resistance, the capacitance value of the pseudo capacitor of the pseudo insulation resistance circuit change, set of pseudo capacitor insulation performance diagnostic apparatus, characterized in that the amplitude of the output voltage of the detection circuit by the change to set the capacitance value when the lowest value on the capacitance value of the pseudo capacitor Method.
In pseudo setting of the capacitor insulation performance diagnostic apparatus according to claim 8,
Wherein the resistance value of the known resistance, pseudo setting of the capacitor insulation performance diagnostic apparatus characterized by setting the same resistance value and the resistance value of the pseudo insulation resistance of the pseudo insulation resistance circuits.

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