JP5448545B2 - Electric leakage detection device for vehicles - Google Patents

Description

  The present invention relates to a vehicle leakage detection device that detects a leakage of a power supply circuit to a chassis ground.

  Conventionally, a technique described in Patent Literature 1 is known as a technique for detecting a ground fault between a driving power source mounted on an electric vehicle such as a hybrid vehicle and a vehicle body.

  In the technique described in Patent Document 1, a positive terminal of a DC power supply is connected to one end of a coupling capacitor, a rectangular wave pulse signal is applied to a measurement point on the other end of the coupling capacitor, and the amplitude of the response waveform A ground fault is detected by measuring a differential voltage corresponding to the above and comparing the differential voltage with a threshold value.

Japanese Patent No. 3783633

  However, since the potential of the response waveform changes as a whole when the battery voltage fluctuates, the conventional method of simply looking at the amplitude has caused a ground fault and the response waveform has a smaller amplitude. The threshold may be exceeded. As a result, the reliability of the ground fault determination is lowered, and there is a risk of erroneous determination.

According to a first aspect of the present invention, there is provided a signal leakage detecting device for applying a test signal having a periodic waveform to a battery power supply circuit electrically insulated from a chassis ground of a vehicle via a coupling capacitor. , A measuring means for measuring the potential of the response waveform when the inspection signal is applied, and a leakage judgment potential threshold based on the measured response waveform potential and the allowable insulation resistance value, And a determination means for determining the response waveform, the leak determination potential threshold is increased in accordance with the overall increase tendency of the response waveform due to the battery voltage increase variation, and the entire response waveform due to the battery voltage decrease variation The leak determination potential threshold value is lowered according to a general decreasing tendency .
According to a second aspect of the present invention, in the vehicle leakage detection device according to the first aspect, the inspection signal is a rectangular wave signal composed of a high section and a low section, and the response waveform high section for each cycle of the response waveform. And calculating a representative value between the maximum measurement value and the minimum measurement value in the interval corresponding to the low interval, and determining the upper limit threshold value and the lower limit threshold value of the leak determination potential threshold value by setting the representative value to the median value. Features.
According to a third aspect of the present invention, in the vehicle leakage detection device according to the second aspect, the determining means is configured such that the maximum measured value in the section corresponding to the high section of the response waveform is less than the upper threshold and the section corresponding to the low section of the response waveform. Only when the minimum value of the section exceeds the lower limit side threshold value, it is determined that there is a leakage.
According to a fourth aspect of the present invention, in the vehicle leakage detection device according to the third aspect, the determination of leakage is performed for each cycle of the response waveform, and when the cycle determined to be leakage continues for a predetermined number of times, finally, It is characterized by determining that an electric leakage has occurred.
According to a fifth aspect of the present invention, there is provided a vehicle leakage detecting apparatus that measures a voltage obtained by resistively dividing a voltage of a battery that is electrically insulated from a chassis ground of the vehicle, and the change in the measured voltage is greater than the change in the leak determination voltage. A DC type electric leakage detection device for a vehicle that determines that electric leakage to the chassis ground of a battery power supply circuit when large is included, and the electric leakage detection device for a vehicle according to any one of claims 1 to 4, comprising: A final leakage determination is performed based on the detection result of the vehicle leakage detection device of the type and the vehicle leakage detection device according to any one of claims 1 to 4 .

  According to the present invention, leakage detection with higher reliability can be performed.

1 is a diagram illustrating a first embodiment of a vehicle leakage detection apparatus. It is a figure explaining an output waveform and a response waveform. It is a figure which shows the flowchart which shows a leak determination procedure. It is a figure which shows a determination table, (a) shows the case where an AC system is used, (b) shows the case where both an AC system and a DC system are used. It is a figure which shows 2nd Embodiment of the leak detection apparatus for vehicles. It is a figure explaining the change of electric potential Vo1 and Vo2 by leak generation.

-First embodiment-
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a vehicle electric leakage detection device according to a first embodiment, and shows a case where it is applied to a drive system for a vehicular rotating electrical machine. The drive system shown in FIG. 1 includes a battery 1, an inverter device 2, a motor 3 for driving a vehicle, a relay circuit, and a battery control unit (hereinafter referred to as BCU) 4. The DC power from the battery 1 is converted into three-phase AC power by the inverter device 2, and the motor 3 is driven by the three-phase AC power.

  The battery 1 is an assembled battery in which a plurality of unit cells BC are connected in series, and is connected to the inverter device 2 through high voltage lines HV + and HV−. The high voltage lines HV + and HV− are provided with relay circuits for connecting and disconnecting the battery 1 and the inverter device 2. The relay circuit includes main relays 10 and 11, a sub relay 12 and a resistor 13. A smoothing capacitor 14 is provided in parallel with the inverter device 2 between the high voltage lines HV + and HV−. The high voltage lines HV + and HV− are normally insulated from the chassis ground of the vehicle.

  Since the charge of the smoothing capacitor 14 is substantially zero at the start of the operation of the inverter device 2, in order to prevent an inrush current when the relay circuit is turned on, first, the main relay 11 and the sub-relay 12 are turned on to pre-set the smoothing capacitor 14. Charge. When the precharge is completed, the main relay 10 is turned on and the sub relay 12 is turned off. Since the precharge current flows into the smoothing capacitor 14 through the resistor 13, it is possible to prevent welding of the relay and to prevent an excessive current from flowing to the single cell BC.

  The BCU 4 is provided with a microcomputer 16 and a leak detection circuit 17. The ground of the BCU 4 is connected to the chassis ground. The leak detection circuit 17 is connected to the positive high voltage line HV + via the coupling capacitor 20. The microcomputer 16 outputs a rectangular wave signal of 0-5V as a leak detection pulse, and detects the voltage generated at one end (measurement point A) of the coupling capacitor 20 as a leak detection response, whereby the battery 1 and the high voltage line HV + are detected. , HV- is diagnosed whether a leak (ground fault) has occurred in the vehicle-side chassis ground.

  The rectangular wave signal output from the microcomputer 16 is output to the measurement point A via the amplifier circuit 21 and the resistor 22. On the other hand, the leak detection response from the measurement point A is input to the microcomputer 16 via the operational amplifier 23 and converted into a digital signal by the A / D converter of the microcomputer 16 and detected. The microcomputer 16 transmits the leak detection result to the host controller 30 on the vehicle side by CAN communication.

(Explanation of leak detection operation)
FIG. 2 is a diagram illustrating an output waveform and a response waveform of a rectangular wave signal. The rectangular wave signal shown in FIG. 2A is a 50% duty signal having an amplitude of 0-5V and a frequency of 10 Hz. This is only an example, and the amplitude, duty, and frequency of the rectangular wave signal are not limited thereto. In the present embodiment, the coupling capacitor 20 is connected to the positive high voltage line HV + of the battery 1, but may be connected to the negative high voltage line HV−. Since the battery 1 has a small internal impedance, a negative leak can be detected even when connected to the positive side.

  When a rectangular wave signal as shown in FIG. 2A is applied to the high voltage line HV + via the coupling capacitor 20, the A / D converter of the microcomputer 16 has a waveform as shown in FIG. A signal (response waveform) is detected. The arrow shown at the lower side of the response waveform in FIG. 2B indicates the AD sampling timing. As an example, the sampling timing when the sampling period is 10 ms is shown. The sampling timing includes at least the timing immediately after the rising / falling of the rectangular wave output, and is set so as to capture the maximum value / minimum value of the response waveform.

  In FIG. 2B, symbols H1 to H5 and L0 to L5 represent AD read values, and the AD read values H1 to H5 are sampled when the rectangular wave signal is at the “H (5V)” level. The AD read values L0 to L5 are sampled when the rectangular wave signal is at the “L (0 V)” level. The AD read value L0 is the same as the AD read value L5 in the previous cycle.

  In general, the response waveform is superimposed on the total voltage (for example, about 300 V) of the battery 1, and the voltage increases or decreases when the battery 1 is charged / discharged or the inverter device 2 is driven. . As described above, the ground of the BCU 4 has the same potential as the chassis ground of the vehicle. However, since the battery 1 is floating with respect to the ground, the potential of the battery 1 is relatively increased or decreased with respect to the chassis ground. That also affects the response waveform.

  The response waveform shown in FIG. 2B shows a case where there is no fluctuation in the total voltage. In the conventional leak detection, when the leak occurs, the magnitude of the amplitude due to the occurrence of the response waveform is detected to determine the leak. I am doing. Since the amplitude of the response waveform decreases when a leak occurs, conventionally, it is determined whether or not the leak is based on whether or not the amplitude is within a threshold range.

  However, the actual response waveform is affected by up and down of the total voltage, and the response waveform shown in FIG. 2B becomes a waveform as shown in FIG. FIG. 2 (c) shows a case where the total voltage is gradually lowered, and the response waveform tends to be generally lowered. As a result, in FIG. 2B, the response waveform is within the threshold range, but in the waveform as in FIG. 2C, the response waveform amplitude is in the H (high level) section of the rectangular wave output. Since it differs depending on the case of the L (low level) section, there is a case where there is a difference in the determination of leak occurrence depending on which of the amplitudes in the H section or the L section. For this reason, the conventional method for determining the occurrence of leakage based on whether the amplitude of the response waveform is within a fixed range has a risk of erroneous determination.

  Therefore, in the present embodiment, highly reliable leak detection that can prevent erroneous determination is performed by performing determination processing as described below on the response waveform as illustrated in FIG. Can do.

  Next, the procedure of the leak determination process in the present embodiment will be described with reference to the flowchart of FIG. 3 and FIG. When the vehicle is activated and the BCU 4 is activated, the leak determination process of FIG. 3 starts.

  In step S100, the count number n of the number of consecutive leak occurrences is reset to zero. In step S110, an intermediate value Hmid of the response waveform in the H (high level) section is calculated based on the acquired AD read values L0, H1 to H5. First, among the AD read values L0, H1 to H5, the data maximum value Hmax having the largest value is set, and the data having the smallest value is set to the minimum value Hmin. Then, an intermediate value between the maximum value Hmax and the minimum value Hmin, that is, an intermediate value Hmid = (Hmax + Hmin) / 2 of the response waveform in the H section is calculated.

  In step S120, an intermediate value Lmid of the response waveform in the L (low level) section is calculated based on the acquired AD read values H5, L1 to L5. First, the largest data value Lmax having the largest value among the AD read values H5, L1 to L5 is set, and the smallest value is set to the minimum value Lmin. As in the case of the H section, an intermediate value (Lmax + Lmin) / 2 between the maximum value Lmax and the minimum value Lmin is calculated, and this is set as the intermediate value Lmid of the response waveform in the L section.

  When the maximum value Hmax and minimum value Hmin of the H section are obtained, the AD read value L0 detected immediately before the H section is also used as data, and the maximum value Lmax and minimum value Lmin of the L section are obtained. The reason why the AD read value H5 detected immediately before the L section is also used as data is that the maximum / minimum value of the response waveform can be taken in as described above.

  In step S130, an intermediate value (Hmid + Lmid) / 2 of the intermediate values Hmid and Lmid of the H section and L section calculated in steps S110 and S120 is calculated, and the intermediate value Mid (representative value) of the response waveform in one cycle period is calculated. And That is, the intermediate value Mid is equal to an intermediate value (Hmax + Hmin + Lmax + Lmin) / 4 between the maximum value Hmax and minimum value Hmin in the H section and the maximum value Lmax and minimum value Lmin in the L section.

  In step S140, threshold values Hvth and Lvth used for leak determination in this one cycle period are calculated. As shown in FIG. 2C, the threshold value Hvth is an upper threshold value with respect to the response waveform, and is set to a value (Hvth = Mid + ADth) larger than the intermediate value Mid by ADth. On the other hand, the threshold value Lvth is a lower threshold value with respect to the response waveform, and is set to a value (Hvth = Mid−ADth) smaller than the intermediate value Mid by ADth. Here, ADth is a value determined from the allowable value of the insulation resistance value (leakage resistance value), and the value obtained by AD converting the amplitude of the response waveform at the allowable insulation resistance value corresponds to 2 · ADth.

  In step S150, flags for the H and L sections are set based on the maximum value Hmax and the minimum value Lmin for the H section obtained in steps S110 and S120, and the threshold values Hvth and Lvth set in step S140, respectively. . The flag Hflag of the H section is set to Hflag = 1 when the condition “Hmax ≧ Hvth” is satisfied. On the other hand, the flag Lflag of the L section is set to Lflag = 1 when the condition “Lmin ≦ Lvth” is satisfied.

  In step S160, it is determined using the determination table shown in FIG. 4A whether or not a leak has occurred in a cycle. The first line of the determination table is when both flags Hflag and Lflag are 0. In this case, the response waveform is inside the lines indicated by the threshold values Hvth and Lvth shown in FIG. 2C, and it is determined that a leak has occurred. This is because, for example, when the response waveform is as shown in FIG. 2B, that is, when the intermediate value of the response waveform is constant and does not change, the amplitude is smaller than the width between lines indicated by the threshold values Hvth and Lvth. It corresponds to.

  First, the second and third lines of the determination table will be described. This is a determination condition provided in consideration of the case where the response waveform has a tendency to decrease or increase overall. When there is a decreasing tendency as shown in FIG. 2C, the data immediately before the change from the H section to the L section (AD reading value H5) is larger in the AD reading value than when there is no overall decreasing tendency. Becomes smaller. That is, the change from the AD read value L0 to the AD read value H5 is compressed. On the contrary, in the L section, the change from the AD read value H5 to the AD read value L5 increases.

  As described above, since the intermediate value Mid is an intermediate value between the intermediate value Hmid of the H section and the intermediate value Lmid of the L section, the intermediate value Mid is moved downward according to the decreasing tendency of the response waveform. When the response waveform tends to decrease, as shown in FIG. 2C, even if no leak has occurred, the maximum value Hmax of the H section has the threshold value Hvth as if a leak has occurred. May fall below. In addition, the response waveform of FIG.2 (c) shows the response waveform when the leak has not generate | occur | produced.

  On the other hand, in the L section, the minimum value Lmin is lower than the threshold value Lvth, and the amount of decrease becomes larger as the response waveform decreases more. Therefore, in the present embodiment, as shown in the second row of the determination table, even if one flag Hflag is 0, it is determined that no leak has occurred when the other flag Lflag is 1. I did it.

  On the other hand, when the entire response waveform tends to increase, contrary to the case shown in FIG. 2C, the minimum value Lmin tends to exceed the threshold value Lvth even if no leak occurs. In the present embodiment, in consideration of such a case, as shown in the third row of the determination table, if one flag Lflag is 0 but the other flag Hflag is 1, no leak has occurred. judge.

  In addition, when the response waveform protrudes in the vertical direction of the lines indicated by the threshold values Hvth and Lvth, that is, when both the flags Hflag and Lflag are 1, a leak occurs as shown in the fourth row of the determination table. It is determined that it has not occurred.

  If it is determined in step S160 that no leak has occurred, the process returns to step S100, the count number n is reset to zero, and the processing from step S110 to step S160 is performed for the next one cycle. On the other hand, if it is determined in step S160 that a leak has occurred, the process proceeds to step S170, where the number of consecutive leak occurrences n is increased by 1, and n = 1.

  In step S180, it is determined whether or not the count number n of continuous leak occurrences is equal to or greater than the prescribed number. If it is determined yes, the process proceeds to step S190, and a leak abnormality signal is reported from the BCU 4 to the host controller 30. . On the other hand, if it is determined to be no, the process proceeds to step S110, and the processes from step S110 to step S160 are performed for the next one cycle. When the processing in step S190 is completed, the leak determination processing program is terminated. If it is not determined in step S190 that the leak is abnormal, the processing up to step S180 is repeatedly executed, and the leakage determination processing program is terminated when the apparatus is stopped.

  In step S180, the specified number of times is determined as appropriate according to the apparatus in order to determine the leakage abnormality, but is set as follows as an example. After the apparatus is started, the prescribed number of times required for determination is set to 20 times, that is, the determination time is 2 seconds until the precharge of the smoothing capacitor 14 is finished and the main relay 10 is turned on. Then, after the main relay is turned on, the determination time is changed to 5 seconds (specified number 50).

  Here, the reason why the determination time until the main relay 10 is turned on is shorter is that it is preferable not to turn on the main relay 10 when there is a leak abnormality, so at least once before turning on the main relay 10. Is set as described above so that the leak abnormality can be determined. Therefore, the specified number of times from the start of the device to the turning on of the main relay is set according to the time required from the start of the device to turning on of the main relay.

  As described above, the ground of the BCU 4 is the chassis ground, but the ground of the battery 1 is in a floating state, so that the potential changes suddenly when starting or when the main relay is turned on. There are times when the potential is extremely different. In that case, the response waveform normally in the range of 0-5V may stick to the upper side or the lower side. In such a case, the leak determination cannot be made. Therefore, in steps S110 and S120, data having a reading value of 0.01 V or less or 4.9 V or more is ignored. Further, when data of 0.01 V or less or 4.9 V or more continues continuously for a predetermined time (for example, 2 minutes) or more, it reports to the host controller 30 that there is an abnormality in the apparatus.

  In addition, since the chassis ground and the battery voltage change transiently at the moment when the relay is connected, it takes several seconds for the transient to settle, so leak diagnosis cannot be performed during that time. Do.

  The ADth value set corresponding to the above-described allowable value of the leak resistance is stored in advance in the memory of the BCU 4. By the way, a plurality of ADth values may be stored in the memory in association with a plurality of different allowable resistance values. You may make it select according to the difference in the specification of a battery system. Switching of the ADth value is performed by sending a command from the host controller 30 via CAN. Further, instead of storing a plurality of ADth values in the memory, the ADth value may be transmitted from the host controller 30 to rewrite the ADth value in the memory.

  As described above, in the present embodiment, the intermediate value Mid is obtained for each cycle, “Mid + ADth” is set as the upper threshold value Hvth for the intermediate value Mid, and “Mid−ADth” is set as the lower threshold value Lvth. It is said. Therefore, when the entire response waveform tends to increase or decrease due to fluctuations in the total voltage or the like, the intermediate value Mid and the threshold values Hvth and Lvth also change following the change in the entire response waveform. As a result, leak determination can be performed more accurately without being affected by changes in the entire response waveform. Further, when one of the upper and lower sides of the response waveform is out of the range of the thresholds Hvth and Lvth, it is determined that no leak has occurred, so that erroneous determination can be prevented. As described above, according to the present embodiment, it is possible to perform a leak determination with high reliability without being affected by a change in the entire response waveform.

  Although not shown in the figure, in order to exclude abnormal fluctuations in the response waveform due to single noise or the like in the calculations in steps S110 to S130, each Max in advance is determined from the AD values of L0, H1 to H5 and H5, L1 to L5. There is also a method of obtaining an intermediate value Mid by performing a series of calculations using values excluding values and Min values.

  In this embodiment, the coupling capacitor 20 is connected to the inverter device side with respect to the main relay 10, but may be connected to the battery side with respect to the main relay 10. In this case, the battery-side leak can be detected regardless of whether the main relay 10 is on or off, but the inverter-side leak cannot be detected unless the main relay 10 is turned on.

-Second embodiment-
5 and 6 are diagrams showing the configuration of the second embodiment. The vehicle leakage detection device according to the second embodiment includes a well-known DC leak detection circuit 40 in addition to the leak detection circuit 17 according to the first embodiment that detects a leak by applying a rectangular wave. Based on the detection results of the two leak detection circuits 17 and 40, it is determined comprehensively whether or not a leak has occurred.

  The DC-type leak detection circuit 40 also serves as a resistance voltage dividing circuit for battery total voltage detection, and detects the occurrence of leaks in the high voltage lines HV + and HV− by detecting the total voltage fluctuation due to the leak. Since the details of the leak detection circuit 17 have been described in the first embodiment, the description thereof will be omitted here, and the leak detection circuit 40 will be described below.

  FIG. 5 shows an example of a DC type leak detection circuit 40, and four resistors Rp 1, Rp 2, Rn 1, Rn 2 are connected in series between the positive and negative electrodes of the battery 1. The resistors Rp1, Rp2, Rn1, and Rn2 are set such that the resistance values are Rp1 = Rn1 and Rp2 = Rn2, and the divided voltages of the resistors Rp1 + Rp2 and Rn1 + Rn2 are set equal. In this case, the high voltage lines HV + and HV− of the battery 1 are both connected to the GND of the BCU 4 by resistors Rp1 and Rp2 or Rn1 and Rn2. However, the resistance value is set so as not to affect the leak detection circuit of the first embodiment. The potential between the resistors Rp1 and Rp2 is input to the amplifier 42, and the output Vo1 of the amplifier 42 is input to the microcomputer 16. The potential between the resistors Rn1 and Rn2 is input to the amplifier 43, and the output Vo1 of the amplifier 43 is input to the microcomputer 16.

  A point B between the resistor Rp2 and the resistor Rn2 is maintained at a reference potential (2.5V here) with respect to the chassis ground by the reference power supply 41. Here, it is assumed that VCC of BCU4 is 5V. Therefore, as shown in FIG. 6, the potentials Vo1 and Vo2 of the amplifiers 42 and 43 appear up and down across the potential 2.5V.

  FIG. 6 is a diagram for explaining changes in the potentials Vo1 and Vo2 due to leakage. When there is no leakage, the divided voltage of the resistors Rp1 + Rp2 and the divided voltage of the resistors Rn1 + Rn2 are equal, so that the potentials Vo1, Vo2 are symmetrical with respect to the 2.5V line.

  On the other hand, when a leak occurs between the high-voltage line HV + on the plus side and the chassis ground, the partial pressure of the resistor Rp1 + Rp2 decreases and the partial pressure of the resistor Rn1 + Rn2 increases. For example, when the total voltage of the battery 1 is 300 V, both of the divided voltages are 150 V when no leak occurs. However, when a leak occurs between the high voltage line HV + and the chassis ground, the resistance Rp1 + Rp2 The partial pressure is changed to 100V and the partial pressure of the resistor Rn1 + Rn2 is changed to 200V. Since the potential at the point B is fixed to the reference potential 2.5V by the reference power supply 41, the potentials Vo1 and Vo2 change in a decreasing direction as shown by solid lines in FIG.

  Conversely, when a leak occurs between the negative high voltage line HV− and the chassis ground, the partial pressure of the resistor Rp1 + Rp2 increases and the partial pressure of the resistor Rn1 + Rn2 decreases. As a result, the potentials Vo1 and Vo2 change in an increasing direction as indicated by broken lines in FIG.

  By using the potentials Vo1 and Vo2 that change in accordance with the occurrence of the leak, it is possible to determine which of the high-voltage lines HV + and HV− the occurrence of the leak, and from the magnitude of the change in the potentials Vo1 and Vo2. It can be determined whether or not the leakage resistance has fallen below an allowable value. For example, if the amount of change in the potentials Vo1 and Vo2 is greater than the change in the leak determination voltage, it is determined that a leak has occurred. In this case, the determination can be made with only one of the potentials Vo1 and Vo2.

  The A / D sampling of the potentials Vo1 and Vo2 is set to 10 ms as in the case of the leak detection circuit 17, and the leak determination time is set to 2 seconds, for example. You may make it match with the determination interval of the leak detection circuit 17. The leak diagnosis is started when the BCU 4 is activated. In addition, when the state of charge of the battery 1 decreases and the total voltage falls below a predetermined reference value, the changes in the potentials Vo1 and Vo2 are too small, leading to erroneous diagnosis. In such a case, the leak determination is performed. Not performed. Further, as in the case of the leak detection circuit 17, a plurality of reference values for leak determination may be prepared and the reference values may be switched according to an instruction from the host controller 30.

  In the second embodiment, if the determination result by the DC leak detection circuit 40 is obtained as described above, the leak abnormality is comprehensively determined using the result and the determination result of the leak detection circuit 17. Judgment is made. FIG. 4B shows a determination table for comprehensive determination, and the AC method indicates determination by the leak detection circuit 17 described above. In this case, the AC method result and the DC method result are determined by the OR condition. For this reason, if it is determined that at least one of the AC method and the DC method is a leakage abnormality, the comprehensive determination is determined as a leakage abnormality. Only when it is determined that both the AC method and the DC method are normal, the overall determination is normal.

  As described above, in the leakage detection device for a vehicle according to the second embodiment, the leakage abnormality is comprehensively determined using the results of the two leakage detection circuits 17 and 40 having different detection methods. Even when a leak that can only be detected by the leak detection circuit occurs, a leak abnormality can be reliably detected. As a result, it is possible to improve the reliability related to leak detection. For example, in the case of the DC system, there is a drawback that it is difficult to detect when the middle point of the battery 1 leaks. However, according to the present embodiment, the leak detection circuit 17 detects the leak even in such a case. Can do.

  Each of the embodiments described above may be used alone or in combination. This is because the effects of the respective embodiments can be achieved independently or synergistically. In addition, the present invention is not limited to the above embodiment as long as the characteristics of the present invention are not impaired. For example, a rectangular wave pulse is applied as the inspection signal in the above embodiment, but the rectangular wave may not be used as long as the signal changes periodically.

  1: battery, 2: inverter device, 3: motor, 4: battery control unit, 14: smoothing capacitor, 16: microcomputer, 17, 40: leak detection circuit, 20: coupling capacitor, 30: host controller, BC: single Battery, HV +, HV-: High voltage line

Claims (5)

A signal applying means for applying a test signal having a periodic waveform to a battery power circuit electrically insulated from the chassis ground of the vehicle via a coupling capacitor;
Measuring means for measuring the potential of the response waveform when the inspection signal is applied;
Determination means for determining leakage of the power supply circuit to the chassis ground based on a potential of the measured response waveform and a leakage determination potential threshold value based on an allowable insulation resistance value;
The leak determination potential threshold is increased in accordance with an overall increase tendency of the response waveform due to an increase variation in the battery voltage, and an overall decrease trend in the response waveform due to a decrease variation in the battery voltage. The leakage detection device for a vehicle is characterized in that the leakage determination potential threshold value is lowered according to the above . In the vehicle electric leakage detection device according to claim 1,
The inspection signal is a rectangular wave signal composed of a high interval and a low interval,
For each cycle of the response waveform, a representative value between the maximum measurement value and the minimum measurement value in a section corresponding to the high section and the low section of the response waveform is calculated, and an upper limit threshold and a lower limit of the leak determination potential threshold A vehicle earth leakage detection device, wherein a side threshold value is determined by setting the representative value to a median value. In the vehicle leakage detection device according to claim 2,
When the maximum measured value in the high-corresponding section of the response waveform is below the upper threshold value and the minimum value in the low-corresponding section of the response waveform is above the lower threshold value, the determination means Only, it is determined that there is an electric leakage. In the vehicle electric leakage detection device according to claim 3,
Leakage detection for a vehicle characterized in that the determination of leakage is performed every cycle of the response waveform, and when the cycle determined to be leakage continues for a predetermined number of times, it is finally determined that leakage has occurred. apparatus. A voltage obtained by resistively dividing the voltage of a battery that is electrically insulated from the chassis ground of the vehicle is measured, and when the change in the measured voltage is larger than the change in the leak determination voltage, the chassis ground of the battery power supply circuit A DC type electric leakage detection device for a vehicle that is determined to be an electric leakage to the vehicle,
The vehicle leakage detection device according to any one of claims 1 to 4,
A vehicle having a final leakage determination based on a detection result of the DC leakage detection device for a vehicle and the leakage detection device for a vehicle according to any one of claims 1 to 4. Earth leakage detection device.

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