WO2017073031A1 - Electric leak detection device and electric leak detection method - Google Patents

Electric leak detection device and electric leak detection method Download PDF

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Publication number
WO2017073031A1
WO2017073031A1 PCT/JP2016/004611 JP2016004611W WO2017073031A1 WO 2017073031 A1 WO2017073031 A1 WO 2017073031A1 JP 2016004611 W JP2016004611 W JP 2016004611W WO 2017073031 A1 WO2017073031 A1 WO 2017073031A1
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leakage
signal
amplitude
noise
leakage detection
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PCT/JP2016/004611
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French (fr)
Japanese (ja)
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山下　誠
達也 呉浦
晴彦 関野
耕治 松川
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パナソニックＩｐマネジメント株式会社
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Publication of WO2017073031A1 publication Critical patent/WO2017073031A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
    • G01R31/52—Testing for short-circuits, leakage current or ground faults

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  • the present invention relates to a leakage detection device and a leakage detection method for detecting leakage in a high voltage circuit.
  • a vehicle such as an electric vehicle is equipped with a high voltage circuit including a high voltage power source such as a storage battery as a power source.
  • a high voltage circuit is insulated from the vehicle body grounded to the ground, the low voltage circuit for driving the in-vehicle device, and the like for the safety of the vehicle user.
  • leakage may occur between the high voltage power supply and the ground or the low voltage circuit. Since such electric leakage leads to the danger of the user, devices for detecting electric leakage are widespread.
  • Patent Literature 1 discloses a leakage detection device that avoids such erroneous detection.
  • the present invention provides a leakage detection device and a leakage detection method capable of determining the presence or absence of leakage even when low-frequency noise is generated.
  • the leakage detection device of the present invention includes a signal output unit, a signal extraction unit, and a leakage determination unit.
  • the signal output unit outputs a test signal to the high voltage circuit via the detection resistor and the coupling capacitor.
  • the signal extraction unit adjusts the inspection signal at the node between the detection resistor and the coupling capacitor, and outputs an extraction signal.
  • the leakage determination unit detects a leakage in the high voltage circuit based on the amplitude of the extracted signal. When the difference between the median amplitude in the current cycle of the extracted signal and the reference value set based on the median amplitude in the past cycle of the extracted signal is within the allowable range, the leakage determination unit The leakage detection result based on the amplitude in the cycle is output. Further, when this difference is outside the allowable range, an effective leakage detection result based on the amplitude in the current cycle is not output.
  • an inspection signal is output to a high voltage circuit via a detection resistor and a coupling capacitor. Further, the inspection signal at the node between the detection resistor and the coupling capacitor is adjusted, and an extraction signal is output. Then, the leakage of the high voltage circuit is detected based on the amplitude of the extracted signal. At this time, it is determined whether or not the difference between the median amplitude of the extracted signal in the current cycle and the reference value set based on the median amplitude of the extracted signal in the past cycle is within an allowable range. . If it is determined that the difference is within the allowable range, a leakage detection result based on the amplitude in the current cycle is output. If it is determined that the difference is outside the allowable range, an effective leakage detection result based on the amplitude in the current cycle is not output.
  • FIG. 1 is a block diagram illustrating an example of a configuration of a leakage detection apparatus according to an embodiment of the present invention.
  • FIG. 2A is a diagram illustrating an example of a waveform of an extraction signal when there is no influence of leakage and all the high voltage circuits are operating normally.
  • FIG. 2B is a diagram illustrating an example of a waveform of an extraction signal when leakage occurs.
  • FIG. 3A is a diagram illustrating an example of a waveform of an extraction signal when low-frequency noise occurs.
  • FIG. 3B is a diagram illustrating an example of a waveform of an extraction signal when high-frequency noise occurs.
  • FIG. 4 is a flowchart for explaining an operation example of the leakage detection device.
  • FIG. 4 is a flowchart for explaining an operation example of the leakage detection device.
  • FIG. 5A is a diagram for explaining a method of calculating the median value Vc in a certain cycle when there is no low frequency noise.
  • FIG. 5B is a diagram for describing a case where the amplitude of the extracted signal is calculated to be smaller than the original amplitude due to the influence of low-frequency noise.
  • FIG. 5C is a diagram for describing a case where the amplitude of the extracted signal is calculated larger than the original amplitude due to the influence of low-frequency noise.
  • FIG. 6A is a diagram illustrating a case where the start of the leakage determination cycle is an increase timing of the extraction signal.
  • FIG. 6B is a diagram illustrating a case where the start of the leakage determination cycle is a decrease timing of the extraction signal.
  • FIG. 7 is a diagram for explaining a method of setting the noise detection threshold value Vthn.
  • the leakage detection device disclosed in Patent Document 1 calculates the median value between the high-side peak value and the low-side peak value of the voltage value at the connection point between the detection resistor and the coupling capacitor. When the difference between the median value and the predetermined reference value is equal to or greater than the predetermined upper limit value, the leakage detection unit determines that a false detection has occurred.
  • the reference value serving as a reference for determining whether or not there is a false detection is a predetermined fixed value. For this reason, in this leakage detection device, for example, when a state in which the voltage value is separated from the reference value by a predetermined upper limit value or more continues for a plurality of amplitude periods, during that period, it continues to be determined as a false detection and the presence or absence of leakage is detected. Cannot judge. Such a disadvantage can occur, for example, when low-frequency noise occurs on the high-voltage circuit side and the voltage value at the connection point fluctuates due to the influence. However, voltage fluctuations due to low-frequency noise are often not large enough to prevent leakage detection (when the amplitude waveform does not collapse), so it is desirable to detect leakage even when low-frequency noise occurs. Has been.
  • FIG. 1 is a block diagram showing an example of the configuration of a leakage detection apparatus 10 according to an embodiment of the present invention.
  • the leakage detection device 10 is a device that is mounted on, for example, a vehicle and detects leakage of the high voltage circuit 100.
  • the high voltage circuit 100 includes a battery 110 that supplies a high voltage and a load 120 that is driven by the high voltage.
  • the load 120 is a motor for driving an electric vehicle, for example.
  • the high voltage circuit 100 is separated from the ground through an insulation resistor 111. In the high voltage circuit 100, it is assumed in advance that low frequency noise and high frequency noise are generated.
  • the leakage detection device 10 includes a coupling capacitor C0, a signal output unit 11, a detection resistor R0, a signal extraction unit 12, a noise determination unit 13, and a leakage determination unit 14.
  • the detection resistor R0 and the coupling capacitor C0 may not be included in the leakage detection device 10.
  • the coupling capacitor C0 connects the leakage detection device 10 and the high voltage circuit 100 in an AC manner, and insulates the leakage detection device 10 and the high voltage circuit 100 in a DC manner.
  • One end of the coupling capacitor C0 is connected to the high voltage circuit 100 (for example, the negative electrode of the battery 110).
  • the signal output unit 11 outputs an AC inspection signal.
  • the signal output unit 11 is supplied with an offset voltage that is an intermediate voltage of the power supply voltage of the leakage determination unit 14.
  • the signal output unit 11 outputs an AC voltage (for example, a sine wave) whose voltage changes around the offset voltage as a test signal.
  • the signal output unit 11 outputs a test signal to the other end of the coupling capacitor C0 through the detection resistor R0.
  • the detection resistor R0 is a resistor for causing a voltage drop in the inspection signal when a current flows to the high voltage circuit 100 via the coupling capacitor C0.
  • the signal extraction unit 12 adjusts the inspection signal output to the node n1 between the detection resistor R0 and the coupling capacitor C0, and outputs the extraction signal.
  • the signal extraction unit 12 includes, for example, a low-pass filter, a high-pass filter, an amplifier circuit (all not shown), and the like.
  • the signal extraction unit 12 removes high-frequency noise and low-frequency noise from the inspection signal output to the node n1 using a low-pass filter and a high-pass filter, and adjusts the signal to be determinable by the noise determination unit 13 (extracted signal) using an amplifier circuit.
  • the configuration (type and number) of the filter of the signal extraction unit 12 may be selected as appropriate, and may further include only an amplifier circuit without having a filter.
  • the signal extraction unit 12 attempts to remove high-frequency and low-frequency noise using a filter such as a low-pass filter and a high-pass filter in this way, it is difficult to remove all high-frequency noise and low-frequency noise. Noise may be superimposed on the signal.
  • the noise determination unit 13 determines whether noise is occurring. For example, when noise is generated in the high voltage circuit 100, the voltage value of the extracted signal varies due to the influence of the noise. The noise determination unit 13 determines the presence or absence of noise generation based on the voltage fluctuation of the extracted signal. Details of the method of determining the occurrence of noise by the noise determination unit 13 will be described later.
  • the leakage determination unit 14 determines whether or not a leakage has occurred based on the extracted signal adjusted by the signal extraction unit 12 when the noise determination unit 13 does not determine that noise has occurred. .
  • this determination is referred to as “leakage determination”.
  • the leakage determination is performed by a microcomputer or the like constituting the leakage determination unit 14 A / D (analog / digital) conversion of the extracted signal, and the voltage value of the extracted signal is compared with a predetermined threshold value. To do. Then, the leakage determination unit 14 outputs the determination result to the outside, for example, a control system (not shown) of a vehicle on which the leakage detection device 10 is mounted.
  • the leakage determination unit 14 outputs whether or not it is determined that leakage has occurred as a leakage detection result.
  • a vehicle control system (not shown in FIG. 1) electrically disconnects the high voltage circuit 100 from the vehicle body, etc. It is possible to prevent a person who is in contact with the person from getting an electric shock.
  • the signal output unit 11 When the signal output unit 11 outputs an inspection signal that is an alternating current signal having a predetermined period, the signal extraction unit 12 adjusts the inspection signal in which the voltage drop is generated by the detection resistor R0, and the noise determination unit 13 and the leakage determination unit are extracted signals. 14 for output.
  • the noise determination unit 13 determines whether noise is generated based on the extracted signal.
  • the leakage determination part 14 determines the presence or absence of a leakage based on the voltage fluctuation amount of an extraction signal.
  • FIG. 2A and 2B show examples of the waveform of the extracted signal.
  • FIG. 2A is a diagram illustrating an example of a waveform of an extraction signal when there is no influence of leakage and noise and all the high voltage circuits are operating normally. As shown in FIG. 2A, when there is no leakage, the waveform of the extracted signal is a sine wave and the amplitude is constant.
  • FIG. 2B is a diagram illustrating an example of a waveform of an extraction signal when a leakage occurs.
  • the amplitude is different between time t1 and after time t1, and the amplitude is smaller after time t1. This is because the voltage value of the extracted signal is attenuated due to the influence of leakage.
  • the leakage determination unit 14 determines that leakage has occurred when the amount of fluctuation in the amplitude of the extracted signal is greater than or equal to a predetermined threshold value.
  • FIG. 3A and 3B show an example of the waveform of the extracted signal when noise occurs.
  • FIG. 3A is a diagram illustrating an example of a waveform of an extraction signal when low-frequency noise occurs.
  • “x” indicates the median value of the amplitude of the extracted signal
  • “ ⁇ ” vertically long rectangle
  • the median value of the amplitude of the extracted signal fluctuates over time due to low frequency noise.
  • the noise determination unit 13 allows the fluctuation of the voltage value due to the low frequency noise. Therefore, if the fluctuation amount of the median value of the extracted signal is within a predetermined allowable range, the noise is generated. It is determined that it has not occurred.
  • This predetermined allowable range is referred to as a noise allowable range in the present embodiment.
  • the low frequency noise means noise having a lower frequency than the extracted signal.
  • the noise determination unit 13 sets a noise allowable range for allowing a fluctuation in voltage value due to low frequency noise for each period of the extraction signal, and the median value of the amplitude of the extraction signal in a certain period is the noise If it is within the allowable range, it is determined that no noise is generated. That is, when no noise is generated or when low-frequency noise is generated to such an extent that the waveform does not collapse, the median value of the amplitude of the extracted signal is within the allowable noise range. 13 determines that no noise is generated. In this case, the leakage determination unit 14 determines the presence or absence of leakage based on the extracted signal.
  • the noise determination unit 13 determines that noise has occurred when the median value of the amplitude of the extracted signal in the period is outside the allowable noise range. In this case, the leakage determination unit 14 does not determine the presence or absence of leakage in order to prevent erroneous determination of leakage due to the influence of noise.
  • FIG. 3B is a diagram illustrating an example of a waveform of an extraction signal when high-frequency noise occurs.
  • a peak Pn shown in FIG. 3B is a peak whose voltage value fluctuates due to high frequency noise.
  • the leakage determination unit 14 determines that the leakage is not actually occurring even though the leakage has not actually occurred. It may be erroneously determined that the error occurred.
  • the median value of the amplitude of the extracted signal varies greatly, and as shown in FIG.
  • the noise determination unit 13 determines that noise has occurred, and the leakage determination unit 14 does not determine whether there is a leakage based on the determination of the noise determination unit 13. .
  • the high frequency noise means noise having a high frequency compared with the inspection signal.
  • the allowable noise range is set for each cycle of the extracted signal by the noise determination unit 13.
  • FIG. 4 is a flowchart for explaining an operation example of the leakage detection device 10.
  • step S1 the noise determination unit 13 determines whether or not noise is generated for each cycle of the extracted signal. This determination is performed by determining whether or not the fluctuation amount of the median value of the amplitude of the extracted signal in a certain cycle is within the allowable noise range shown in FIGS. 3A and 3B. More specifically, when the median amplitude of the extracted signal in a certain cycle is Vc, the noise detection reference value is Vc_std, and the noise detection threshold value is Vthn, the noise determination unit 13 calculates the following formula (1 ) Is satisfied, it is determined that the fluctuation amount of the voltage value of the extracted signal is within the allowable noise range, and no noise is generated.
  • the noise determination unit 13 determines that the amount of fluctuation in the median value of the amplitude of the extracted signal is outside the allowable noise range, and determines that noise has occurred. The method for setting these parameters will be described in detail later.
  • Expression (1) is an expression for determining whether or not the median value Vc of the amplitude of the extracted signal is within the noise detection range Vc_std ⁇ Vthn.
  • step S1 when the noise determination unit 13 determines in step S1 that no noise is generated, the flow proceeds to step S2. On the other hand, if the noise determination unit 13 determines that noise has occurred in step S1, the flow proceeds to step S6.
  • step S1 it is not determined that noise is generated even if low-frequency noise such as that illustrated in FIG. 3A is generated. Then, when noise that causes a steep waveform change in a short time as illustrated in FIG. 3B has occurred, it is determined that noise has occurred.
  • the noise detection threshold value Vthn in the above formula (1) is set to be larger than the change in waveform caused by the low frequency noise as illustrated in FIG. 3A. For this reason, in step S1, when low frequency noise is generated, the fluctuation of the voltage value due to the low frequency noise is smaller than the threshold value Vthn. Therefore, the noise determination unit 13 generates noise. Judge that there is no.
  • step S2 the leakage determination unit 14 determines whether or not a leakage has occurred in the circuit.
  • the determination of leakage by the leakage determination unit 14 is performed by detecting whether or not the amplitude of the extracted signal in the current period is attenuated as compared to the case where no leakage has occurred, as shown in FIG. 2B. .
  • the leakage determination unit 14 operates the high-voltage circuit 100 and the leakage detection device 10 in a state where no leakage (and noise) has occurred in advance, acquires the amplitude of the extracted signal in advance, and holds that value.
  • the amplitude in the current cycle is compared with a value acquired in advance, and the difference between the amplitude of the extracted signal in the current cycle and the amplitude when no leakage has occurred, If it is equal to or greater than the leakage detection threshold value Vthl, it is determined that leakage has occurred.
  • the threshold value Vthl for leakage detection which is a determination criterion for leakage detection, is determined in advance based on, for example, the voltage value of the extracted signal when leakage is experimentally generated in the high voltage circuit 100, for example. That's fine.
  • step S2 if the leakage determination unit 14 determines that a leakage has occurred, the flow proceeds to step S3. On the other hand, if the leakage determination unit 14 determines in step S2 that no leakage has occurred, the flow proceeds to step S4.
  • step S3 the leakage determination unit 14 outputs a determination result that leakage has occurred.
  • step S4 the leakage determination unit 14 outputs a determination result that leakage has not occurred.
  • step S5 the noise determination unit 13 outputs the determination result in step S3 or S4, and then sets the noise detection reference value Vc_std in the next period based on the amplitude value or the like of the current period. Details of the method of setting the noise detection reference value Vc_std will be described later.
  • step S6 the leakage determination unit 14 does not determine whether or not there is a leakage in the current cycle, and the result of the leakage determination in the previous cycle is, for example, the vehicle Output to the control system. Thereby, even when it is not possible to determine the presence or absence of leakage due to the influence of noise, it is possible to output a leakage determination result with a certain degree of reliability, that is, the latest leakage determination result.
  • step S7 the process in the current cycle is completed, and the process proceeds to the next cycle.
  • FIG. 5A to FIG. 5C show an example of a method for calculating the median value Vc of the amplitude of the extracted signal when there is no low frequency noise.
  • FIG. 5A is a diagram for explaining a method of calculating the median value Vc in a certain cycle when there is no low frequency noise.
  • the operation of the noise determination unit 13 is performed for each cycle (leakage determination cycle) of the extracted signal as shown in FIG. 4, and the maximum value Vmax and the minimum value of the voltage value of the extracted signal in that cycle.
  • the median value with the value Vmin is the median value Vc of the current period.
  • the median value Vc is calculated using the following mathematical formula (2).
  • FIG. 5B is a diagram for describing a case where the amplitude of the extracted signal is calculated to be smaller than the original amplitude due to the influence of low-frequency noise.
  • FIG. 5C is a diagram for explaining a case where the amplitude of the extracted signal is calculated larger than the original amplitude due to the influence of low frequency noise.
  • FIG. 6A and 6B are diagrams for explaining a calculation method of the median amplitude when the waveform of the extracted signal is fluctuated due to the influence of low frequency noise.
  • FIG. 6A shows a case where the start of the leakage determination cycle is the increase timing of the extraction signal.
  • FIG. 6B shows a case where the start of the leakage determination cycle is the extraction signal decrease timing.
  • Vmax_t0 is the maximum value in the leakage determination cycle t0.
  • Vmax_t1 is the maximum value in the leakage determination cycle t1.
  • Vmin_t0 is the minimum value in the leakage determination cycle t0.
  • Vmin_t1 is the minimum value in the leakage determination cycle t1.
  • Vmin is the median value of Vmin_t0 and Vmin_t1. That is, Vmin is calculated using the following formula (3).
  • the median value Vc is calculated using the following formula (4).
  • the median value Vc is calculated using the following formula (5).
  • the noise detection reference value Vc_std is the median value of the amplitude of the extracted signal when no noise (or leakage) occurs in the high voltage circuit 100.
  • a specific calculation method of the noise detection reference value Vc_std for example, there is the following method.
  • the noise detection reference value Vc_std in the next cycle n + 1 cycle is changed to the median value Vc in the nth cycle which is the current cycle.
  • the moving average for the several cycles A method of setting the value to the noise detection reference value Vc_std in the next period may be adopted.
  • the noise detection reference value Vc_std is changed for each cycle of the extracted signal.
  • the initial value of the noise detection reference value Vc_std is, for example, calculated as the median value of the amplitude of an ideal extracted signal when noise (or leakage) is not generated due to the design of the high voltage circuit 100.
  • the value may be adopted as an initial value.
  • the extraction was performed in a quasi-ideal environment free from noise and leakage when the high voltage circuit 100 and the leakage detection device 10 were shipped.
  • the median value obtained from the actual measurement value of the signal may be set as the initial value of the noise detection reference value Vc_std.
  • FIG. 7 is a diagram for explaining a method of setting the noise detection threshold value Vthn.
  • the dotted sine curve indicates the waveform of the low frequency noise
  • the solid curve indicates the waveform of the extracted signal.
  • the waveform of the extracted signal fluctuates due to the influence of low frequency noise.
  • the noise detection threshold value Vthn is set so as to allow the influence on the extracted signal by the maximum low-frequency noise within a range not exceeding the voltage measurement range. Specifically, in FIG. 7, when the amplitude of the extracted signal is Vamp, the voltage measurement range is Vrange, the period of the extracted signal is t, and the period of the low frequency noise is T, the amplitude of the low frequency noise is (Vrange-Vamp). Therefore, the threshold value Vthn for noise detection, which is the amount of amplitude fluctuation that can be allowed for one cycle of the extracted signal, is calculated as in the following formula (6).
  • the noise detection threshold value Vthn may be set to a value that allows some variation in the extracted signal due to low-frequency noise.
  • the leakage detection device 10 includes the signal output unit 11, the signal extraction unit 12, and the leakage determination unit 14.
  • the signal output unit 11 outputs a test signal to the high voltage circuit 100 via the detection resistor R0 and the coupling capacitor C0.
  • the signal extraction unit 12 adjusts the inspection signal at the node n1 between the detection resistor R0 and the coupling capacitor C0, and outputs an extraction signal.
  • the leakage determination unit 14 detects leakage of the high voltage circuit 100 based on the amplitude of the extracted signal.
  • the leakage determination unit 14 presents the current value when the difference between the median amplitude of the extracted signal in the current cycle and the reference value set based on the median amplitude of the extracted signal in the past cycle is within an allowable range.
  • the leakage detection result based on the amplitude in the period is output. Further, when this difference is outside the allowable range, an effective leakage detection result based on the amplitude in the current cycle is not output.
  • the reference value for calculating the difference from the median amplitude of the extracted signal is not a fixed value, but the median amplitude of the extracted signal in the past cycle. For this reason, when noise (for example, high-frequency noise) having a short period and a large waveform fluctuation amount occurs, the difference is outside a predetermined allowable range (noise allowable range). On the other hand, when noise (for example, low frequency noise) having a long period and a short waveform variation occurs, the difference is within a predetermined allowable range. For this reason, even when low frequency noise occurs, the noise determination unit 13 does not determine that noise has occurred, and the leakage determination unit 14 can determine whether there is leakage.
  • noise for example, high-frequency noise
  • noise for example, low frequency noise
  • the leakage determination unit 14 maintains the result of the leakage determination in the previous cycle as the result of the leakage determination in the current cycle. For this reason, an accurate leakage determination result can be obtained even when the leakage determination is not performed, for example, when high-frequency noise occurs.
  • the leakage determining unit 14 has been described as not determining whether or not there is a leakage in the current cycle. good.
  • the leakage determination result in the current cycle since the leakage determination result in the current cycle may be erroneously determined, the leakage determination result in the current cycle is not output (for example, the leakage determination result itself is not output or the leakage detection result in the previous cycle is not detected). Output the result), or if the leakage determination result in the current cycle is output, it is preferable to output that the leakage determination result is not valid (possibly with a false detection) due to a flag or the like. .
  • the leakage determination unit 14 does not output an effective leakage detection result based on the amplitude in the current cycle.
  • the present invention can be applied to a leakage detection device that detects a leakage of a high voltage circuit mounted on a vehicle, for example.

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Abstract

In the present invention, an electric leak detection device has a signal output unit, a signal extraction unit, and an electric leak determination unit. The signal output unit outputs an inspection signal to a high-voltage circuit via a detection resistor and a coupling capacitor that are connected by a node. The signal extraction unit adjusts the inspection signal at the node and outputs an extraction signal. The electric leak determination unit senses an electric leak in the high-voltage circuit on the basis of the amplitude of the extraction signal. In cases when the difference between the center value of the amplitude in the present period of the extraction signal and a reference value set on the basis of the center value of the amplitude in a past period of the extraction signal is within a permissible range, an electric leak detection result based on the amplitude in the present period is outputted. In cases when the difference is outside the permissible range, no electric leak detection result based on the amplitude in the present period is outputted.

Description

漏電検出装置および漏電検出方法Electric leakage detection device and electric leakage detection method
　本発明は、高電圧回路の漏電を検出する漏電検出装置および漏電検出方法に関する。 The present invention relates to a leakage detection device and a leakage detection method for detecting leakage in a high voltage circuit.
　例えば電気自動車等の車両には、動力源として、蓄電池等の高電圧電源を含む高電圧回路が搭載される。このような高電圧回路は、車両利用者の安全のため、グランドに接地した車体や、車載機器駆動用の低電圧回路等とは絶縁されている。しかし、何らかの原因で高電圧電源とグランドあるいは低電圧回路との間で漏電が生じる場合がある。このような漏電は利用者の危険に繋がるため、漏電を検出する装置が普及している。 For example, a vehicle such as an electric vehicle is equipped with a high voltage circuit including a high voltage power source such as a storage battery as a power source. Such a high voltage circuit is insulated from the vehicle body grounded to the ground, the low voltage circuit for driving the in-vehicle device, and the like for the safety of the vehicle user. However, for some reason, leakage may occur between the high voltage power supply and the ground or the low voltage circuit. Since such electric leakage leads to the danger of the user, devices for detecting electric leakage are widespread.
　このような漏電検出装置では、例えば、カップリングコンデンサを介して交流信号を高電圧回路に印加し、交流信号の振幅変動量から漏電を検出している。しかしながら、ノイズ等に起因して交流信号の振幅変動量が変化することで、実際には漏電していないにもかかわらず、漏電検出装置が漏電していると誤検知してしまう場合がある。このような誤検知を回避する漏電検知装置が、例えば特許文献１に開示されている。 In such a leakage detection device, for example, an AC signal is applied to a high voltage circuit via a coupling capacitor, and the leakage is detected from the amplitude fluctuation amount of the AC signal. However, the amplitude fluctuation amount of the AC signal is changed due to noise or the like, so that it may be erroneously detected that the leakage detection device has a leakage even though the leakage has not actually occurred. For example, Patent Literature 1 discloses a leakage detection device that avoids such erroneous detection.
特開２００７－１０８０７４号公報JP 2007-108074 A
　本発明は、低周波ノイズが発生している場合でも、漏電の有無を判定することができる漏電検出装置および漏電検出方法を提供する。 The present invention provides a leakage detection device and a leakage detection method capable of determining the presence or absence of leakage even when low-frequency noise is generated.
　本発明の漏電検出装置は、信号出力部と、信号抽出部と、漏電判定部と、を有する。信号出力部は、高電圧回路へ検出抵抗およびカップリングコンデンサを介して検査信号を出力する。信号抽出部は、これらの検出抵抗とカップリングコンデンサとの間の結節点における検査信号を調整し、抽出信号を出力する。漏電判定部は、この抽出信号の振幅に基づいて高電圧回路の漏電を検知する。漏電判定部は、抽出信号の現在の周期における振幅の中央値と、抽出信号の過去の周期における振幅の中央値に基づいて設定される基準値との差分が許容範囲内にある場合に現在の周期における振幅に基づいた漏電検出結果を出力する。また、この差分が許容範囲外にある場合に現在の周期における振幅に基づいた有効な漏電検出結果を出力しない。 The leakage detection device of the present invention includes a signal output unit, a signal extraction unit, and a leakage determination unit. The signal output unit outputs a test signal to the high voltage circuit via the detection resistor and the coupling capacitor. The signal extraction unit adjusts the inspection signal at the node between the detection resistor and the coupling capacitor, and outputs an extraction signal. The leakage determination unit detects a leakage in the high voltage circuit based on the amplitude of the extracted signal. When the difference between the median amplitude in the current cycle of the extracted signal and the reference value set based on the median amplitude in the past cycle of the extracted signal is within the allowable range, the leakage determination unit The leakage detection result based on the amplitude in the cycle is output. Further, when this difference is outside the allowable range, an effective leakage detection result based on the amplitude in the current cycle is not output.
　本発明の漏電検出方法では、高電圧回路へ検出抵抗およびカップリングコンデンサを介して検査信号を出力する。また、これらの検出抵抗とカップリングコンデンサとの間の結節点における検査信号を調整し、抽出信号を出力する。そして、抽出信号の振幅に基づいて高電圧回路の漏電を検知する。その際、抽出信号の現在の周期における振幅の中央値と、抽出信号の過去の周期における振幅の中央値に基づいて設定される基準値との差分が許容範囲内にあるか否かを判定する。この差分が許容範囲内にあると判定された場合には、現在の周期における振幅に基づいた漏電検出結果を出力する。差分が許容範囲外にあると判定された場合には、現在の周期における振幅に基づいた有効な漏電検出結果を出力しない。 In the leakage detection method of the present invention, an inspection signal is output to a high voltage circuit via a detection resistor and a coupling capacitor. Further, the inspection signal at the node between the detection resistor and the coupling capacitor is adjusted, and an extraction signal is output. Then, the leakage of the high voltage circuit is detected based on the amplitude of the extracted signal. At this time, it is determined whether or not the difference between the median amplitude of the extracted signal in the current cycle and the reference value set based on the median amplitude of the extracted signal in the past cycle is within an allowable range. . If it is determined that the difference is within the allowable range, a leakage detection result based on the amplitude in the current cycle is output. If it is determined that the difference is outside the allowable range, an effective leakage detection result based on the amplitude in the current cycle is not output.
　本発明によれば、低周波ノイズが発生している場合でも、漏電の有無を判定することができる。 According to the present invention, it is possible to determine the presence or absence of electric leakage even when low-frequency noise is generated.
図１は、本発明の実施の形態の漏電検出装置の構成の一例を示すブロック図である。FIG. 1 is a block diagram illustrating an example of a configuration of a leakage detection apparatus according to an embodiment of the present invention. 図２Ａは、漏電の影響がなく、高電圧回路がすべて正常に作動している場合の抽出信号の波形の一例を示す図である。FIG. 2A is a diagram illustrating an example of a waveform of an extraction signal when there is no influence of leakage and all the high voltage circuits are operating normally. 図２Ｂは、漏電が発生した場合の抽出信号の波形の一例を示す図である。FIG. 2B is a diagram illustrating an example of a waveform of an extraction signal when leakage occurs. 図３Ａは、低周波ノイズが発生した場合の抽出信号の波形の一例を示す図である。FIG. 3A is a diagram illustrating an example of a waveform of an extraction signal when low-frequency noise occurs. 図３Ｂは、高周波ノイズが発生した場合の抽出信号の波形の一例を示す図である。FIG. 3B is a diagram illustrating an example of a waveform of an extraction signal when high-frequency noise occurs. 図４は、漏電検出装置の動作例について説明するためのフローチャートである。FIG. 4 is a flowchart for explaining an operation example of the leakage detection device. 図５Ａは、低周波ノイズがない場合の、ある周期における中央値Ｖｃの算出方法について説明するための図である。FIG. 5A is a diagram for explaining a method of calculating the median value Vc in a certain cycle when there is no low frequency noise. 図５Ｂは、低周波ノイズの影響で、本来の振幅よりも抽出信号の振幅が小さく算出される場合を説明するための図である。FIG. 5B is a diagram for describing a case where the amplitude of the extracted signal is calculated to be smaller than the original amplitude due to the influence of low-frequency noise. 図５Ｃは、低周波ノイズの影響で、本来の振幅よりも抽出信号の振幅が大きく算出される場合を説明するための図である。FIG. 5C is a diagram for describing a case where the amplitude of the extracted signal is calculated larger than the original amplitude due to the influence of low-frequency noise. 図６Ａは、漏電判定周期の開始が抽出信号の増加タイミングである場合を示す図である。FIG. 6A is a diagram illustrating a case where the start of the leakage determination cycle is an increase timing of the extraction signal. 図６Ｂは、漏電判定周期の開始が抽出信号の減少タイミングである場合を示す図である。FIG. 6B is a diagram illustrating a case where the start of the leakage determination cycle is a decrease timing of the extraction signal. 図７は、ノイズ検出用しきい値Ｖｔｈｎの設定方法について説明するための図である。FIG. 7 is a diagram for explaining a method of setting the noise detection threshold value Vthn.
　本発明の実施の形態の説明に先立ち、従来の漏電検知装置における問題点を簡単に説明する。特許文献１に開示された漏電検知装置は、検出抵抗とカップリングコンデンサとの間の接続点の電圧値の高位側のピーク値と低位側のピーク値との中央値を算出する。そして、この中央値と所定の基準値との差分が所定の上限値以上である場合に、漏電検知部は誤検知が発生したと判定する。 Prior to the description of the embodiment of the present invention, problems in the conventional leakage detection device will be briefly described. The leakage detection device disclosed in Patent Document 1 calculates the median value between the high-side peak value and the low-side peak value of the voltage value at the connection point between the detection resistor and the coupling capacitor. When the difference between the median value and the predetermined reference value is equal to or greater than the predetermined upper limit value, the leakage detection unit determines that a false detection has occurred.
　しかしながら、この漏電検出装置では、誤検知か否かを判定する基準となる基準値が所定の固定値である。このため、この漏電検出装置では、例えば電圧値が当該基準値から所定の上限値以上離れた状態が複数の振幅周期に亘って連続した場合、その間、誤検知と判定し続け、漏電の有無を判定することができない。このような不利益は、例えば低周波ノイズが高電圧回路側に発生し、その影響で接続点の電圧値が変動した場合等に生じうる。しかしながら、低周波ノイズによる電圧値の変動は、漏電検出を妨げるほど大きな変動とはならない場合（振幅波形が崩れない場合）が多いため、低周波ノイズが発生した場合でも漏電検知を行うことが要望されている。 However, in this leakage detection device, the reference value serving as a reference for determining whether or not there is a false detection is a predetermined fixed value. For this reason, in this leakage detection device, for example, when a state in which the voltage value is separated from the reference value by a predetermined upper limit value or more continues for a plurality of amplitude periods, during that period, it continues to be determined as a false detection and the presence or absence of leakage is detected. Cannot judge. Such a disadvantage can occur, for example, when low-frequency noise occurs on the high-voltage circuit side and the voltage value at the connection point fluctuates due to the influence. However, voltage fluctuations due to low-frequency noise are often not large enough to prevent leakage detection (when the amplitude waveform does not collapse), so it is desirable to detect leakage even when low-frequency noise occurs. Has been.
　以下、本発明の実施の形態による漏電検出装置について、図面を参照して詳細に説明する。 Hereinafter, a leakage detection apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings.
　＜構成説明＞
　図１は、本発明の実施の形態に係る漏電検出装置１０の構成の一例を示すブロック図である。 <Description of configuration>
FIG. 1 is a block diagram showing an example of the configuration of a leakage detection apparatus 10 according to an embodiment of the present invention.
　漏電検出装置１０は、例えば車両に搭載され、高電圧回路１００の漏電を検出する装置である。高電圧回路１００は、高電圧を供給する電池１１０と、高電圧により駆動する負荷１２０とを有している。負荷１２０は、例えば電気自動車の駆動用モータである。高電圧回路１００は、絶縁抵抗１１１を介してアースと分離されている。高電圧回路１００では、低周波ノイズおよび高周波ノイズが発生することが予め想定される。 The leakage detection device 10 is a device that is mounted on, for example, a vehicle and detects leakage of the high voltage circuit 100. The high voltage circuit 100 includes a battery 110 that supplies a high voltage and a load 120 that is driven by the high voltage. The load 120 is a motor for driving an electric vehicle, for example. The high voltage circuit 100 is separated from the ground through an insulation resistor 111. In the high voltage circuit 100, it is assumed in advance that low frequency noise and high frequency noise are generated.
　漏電検出装置１０は、カップリングコンデンサＣ０、信号出力部１１、検出抵抗Ｒ０、信号抽出部１２、ノイズ判定部１３、および、漏電判定部１４を有している。なお、検出抵抗Ｒ０とカップリングコンデンサＣ０とは漏電検出装置１０に含まれていなくてもよい。 The leakage detection device 10 includes a coupling capacitor C0, a signal output unit 11, a detection resistor R0, a signal extraction unit 12, a noise determination unit 13, and a leakage determination unit 14. The detection resistor R0 and the coupling capacitor C0 may not be included in the leakage detection device 10.
　カップリングコンデンサＣ０は、漏電検出装置１０と高電圧回路１００とを交流的に接続され、漏電検出装置１０と高電圧回路１００とを直流的に絶縁する。カップリングコンデンサＣ０の一端は、高電圧回路１００（例えば電池１１０の負極）に接続される。 The coupling capacitor C0 connects the leakage detection device 10 and the high voltage circuit 100 in an AC manner, and insulates the leakage detection device 10 and the high voltage circuit 100 in a DC manner. One end of the coupling capacitor C0 is connected to the high voltage circuit 100 (for example, the negative electrode of the battery 110).
　信号出力部１１は、交流の検査信号を出力する。信号出力部１１には、漏電判定部１４の電源電圧の中間の電圧であるオフセット電圧が供給される。信号出力部１１は、オフセット電圧を中心に電圧が変化する交流電圧（例えば、正弦波）を、検査信号として出力する。信号出力部１１は、検出抵抗Ｒ０を通して、カップリングコンデンサＣ０の他端に、検査信号を出力する。 The signal output unit 11 outputs an AC inspection signal. The signal output unit 11 is supplied with an offset voltage that is an intermediate voltage of the power supply voltage of the leakage determination unit 14. The signal output unit 11 outputs an AC voltage (for example, a sine wave) whose voltage changes around the offset voltage as a test signal. The signal output unit 11 outputs a test signal to the other end of the coupling capacitor C0 through the detection resistor R0.
　検出抵抗Ｒ０は、カップリングコンデンサＣ０を介して高電圧回路１００へ電流が流れたときに、検査信号に電圧降下を生じさせるための抵抗である。 The detection resistor R0 is a resistor for causing a voltage drop in the inspection signal when a current flows to the high voltage circuit 100 via the coupling capacitor C0.
　信号抽出部１２は、検出抵抗Ｒ０とカップリングコンデンサＣ０との間の結節点ｎ１に出力される検査信号を調整し、抽出信号を出力する。信号抽出部１２は、例えば、ローパスフィルタ、ハイパスフィルタ、増幅回路（何れも不図示）等で構成される。信号抽出部１２は、結節点ｎ１に出力される検査信号からローパスフィルタやハイパスフィルタにより高周波ノイズや低周波ノイズを除去し、増幅回路によりノイズ判定部１３で判定可能な信号（抽出信号）へ調整する。なお、信号抽出部１２のフィルタの構成（種類・数）は適宜選択しても良く、さらに、フィルタを有することなく、増幅回路のみを有する構成であってもよい。 The signal extraction unit 12 adjusts the inspection signal output to the node n1 between the detection resistor R0 and the coupling capacitor C0, and outputs the extraction signal. The signal extraction unit 12 includes, for example, a low-pass filter, a high-pass filter, an amplifier circuit (all not shown), and the like. The signal extraction unit 12 removes high-frequency noise and low-frequency noise from the inspection signal output to the node n1 using a low-pass filter and a high-pass filter, and adjusts the signal to be determinable by the noise determination unit 13 (extracted signal) using an amplifier circuit. To do. Note that the configuration (type and number) of the filter of the signal extraction unit 12 may be selected as appropriate, and may further include only an amplifier circuit without having a filter.
　信号抽出部１２が、このようにローパスフィルタやハイパスフィルタ等のフィルタを使用して高周波および低周波ノイズを除去しようとしても、全ての高周波ノイズや低周波ノイズを除去することは困難であり、抽出信号にはノイズが重畳され得る。 Even if the signal extraction unit 12 attempts to remove high-frequency and low-frequency noise using a filter such as a low-pass filter and a high-pass filter in this way, it is difficult to remove all high-frequency noise and low-frequency noise. Noise may be superimposed on the signal.
　ノイズ判定部１３は、ノイズが発生しているか否かを判定する。例えば高電圧回路１００にノイズが発生している場合、ノイズの影響により抽出信号の電圧値が変動する。ノイズ判定部１３は、この抽出信号の電圧変動に基づいてノイズ発生の有無を判定する。ノイズ判定部１３によるノイズの発生を判定する方法の詳細については後述する。 The noise determination unit 13 determines whether noise is occurring. For example, when noise is generated in the high voltage circuit 100, the voltage value of the extracted signal varies due to the influence of the noise. The noise determination unit 13 determines the presence or absence of noise generation based on the voltage fluctuation of the extracted signal. Details of the method of determining the occurrence of noise by the noise determination unit 13 will be described later.
　漏電判定部１４は、ノイズ判定部１３により、ノイズが発生していると判定されなかった場合に、信号抽出部１２の調整した抽出信号に基づいて、漏電が発生しているか否かを判定する。この判定を、以下では漏電判定と称する。漏電判定は、具体的には、漏電判定部１４を構成するマイクロコンピュータ等が、抽出信号をＡ／Ｄ（アナログ／デジタル）変換し、抽出信号の電圧値と所定のしきい値との比較等により行う。そして、漏電判定部１４は、判定結果を外部、例えば漏電検出装置１０が搭載された車両の制御システム（図示せず）等に出力する。すなわち、漏電判定部１４は、漏電が発生したと判定したか否かを漏電検出結果として出力する。漏電が発生したとの漏電検出結果を漏電判定部１４が出力した場合には、図１に図示しない車両の制御システムが、高電圧回路１００と車体等とを電気的に遮断することで、車体に接した人等が感電する事態を防止することができる。 The leakage determination unit 14 determines whether or not a leakage has occurred based on the extracted signal adjusted by the signal extraction unit 12 when the noise determination unit 13 does not determine that noise has occurred. . Hereinafter, this determination is referred to as “leakage determination”. Specifically, the leakage determination is performed by a microcomputer or the like constituting the leakage determination unit 14 A / D (analog / digital) conversion of the extracted signal, and the voltage value of the extracted signal is compared with a predetermined threshold value. To do. Then, the leakage determination unit 14 outputs the determination result to the outside, for example, a control system (not shown) of a vehicle on which the leakage detection device 10 is mounted. That is, the leakage determination unit 14 outputs whether or not it is determined that leakage has occurred as a leakage detection result. When the leakage determination unit 14 outputs a leakage detection result indicating that a leakage has occurred, a vehicle control system (not shown in FIG. 1) electrically disconnects the high voltage circuit 100 from the vehicle body, etc. It is possible to prevent a person who is in contact with the person from getting an electric shock.
　＜動作説明＞
　以下、漏電検出装置１０の動作について説明する。信号出力部１１が所定周期の交流信号である検査信号を出力すると、検出抵抗Ｒ０によって電圧降下が生じた検査信号を、信号抽出部１２が調整し、抽出信号としてノイズ判定部１３および漏電判定部１４に出力する。ノイズ判定部１３は抽出信号に基づいてノイズが発生しているか否かを判定する。また、漏電判定部１４は、抽出信号の電圧変動量に基づいて、漏電の有無を判定する。 <Description of operation>
Hereinafter, the operation of the leakage detection device 10 will be described. When the signal output unit 11 outputs an inspection signal that is an alternating current signal having a predetermined period, the signal extraction unit 12 adjusts the inspection signal in which the voltage drop is generated by the detection resistor R0, and the noise determination unit 13 and the leakage determination unit are extracted signals. 14 for output. The noise determination unit 13 determines whether noise is generated based on the extracted signal. Moreover, the leakage determination part 14 determines the presence or absence of a leakage based on the voltage fluctuation amount of an extraction signal.
　図２Ａ、図２Ｂは、抽出信号の波形の例を示している。図２Ａは、漏電およびノイズの影響がなく、高電圧回路がすべて正常に作動している場合の抽出信号の波形の一例を示す図である。図２Ａに示すように、漏電が発生していない場合、抽出信号の波形は正弦波であり、その振幅は一定となる。 2A and 2B show examples of the waveform of the extracted signal. FIG. 2A is a diagram illustrating an example of a waveform of an extraction signal when there is no influence of leakage and noise and all the high voltage circuits are operating normally. As shown in FIG. 2A, when there is no leakage, the waveform of the extracted signal is a sine wave and the amplitude is constant.
　図２Ｂは、漏電が発生した場合の抽出信号の波形の一例を示す図である。図２Ｂにおいて、時刻ｔ１までと時刻ｔ１以降とで振幅が異なっており、時刻ｔ１以降の方が振幅が小さい。これは、漏電の影響によって抽出信号の電圧値が減衰しているからである。 FIG. 2B is a diagram illustrating an example of a waveform of an extraction signal when a leakage occurs. In FIG. 2B, the amplitude is different between time t1 and after time t1, and the amplitude is smaller after time t1. This is because the voltage value of the extracted signal is attenuated due to the influence of leakage.
　図２Ｂに示すように、漏電が発生している場合、抽出信号の波形は、発生していない場合と比較して減衰する。漏電判定部１４は、このような性質に基づいて、抽出信号の振幅の変動量が所定のしきい値以上に大きくなった場合に、漏電が発生したと判定する。 As shown in FIG. 2B, when leakage occurs, the waveform of the extracted signal is attenuated compared to when it does not occur. Based on such properties, the leakage determination unit 14 determines that leakage has occurred when the amount of fluctuation in the amplitude of the extracted signal is greater than or equal to a predetermined threshold value.
　次に、回路にノイズが発生した場合の漏電検出装置１０の挙動について説明する。図３Ａ、図３Ｂは、ノイズが発生した場合の抽出信号の波形の一例を示している。図３Ａは、低周波ノイズが発生した場合の抽出信号の波形の一例を示す図である。図３Ａ、図３Ｂにおいて、「×」は抽出信号の振幅の中央値を示しており、「□」（縦長長方形）はノイズ許容範囲のイメージを示している。図３Ａに示すように、低周波ノイズによって、抽出信号の振幅の中央値は時間の経過とともに上下している。 Next, the behavior of the leakage detection device 10 when noise occurs in the circuit will be described. 3A and 3B show an example of the waveform of the extracted signal when noise occurs. FIG. 3A is a diagram illustrating an example of a waveform of an extraction signal when low-frequency noise occurs. 3A and 3B, “x” indicates the median value of the amplitude of the extracted signal, and “□” (vertically long rectangle) indicates an image of the allowable noise range. As shown in FIG. 3A, the median value of the amplitude of the extracted signal fluctuates over time due to low frequency noise.
　しかしながら、低周波ノイズによる抽出信号の電圧値の変動量は小さく（ノイズによって抽出信号の振幅の波形は崩れず）、漏電判定部１４による漏電の判定を妨げない場合が多い。このような低周波ノイズが発生した場合、抽出信号の振幅の中央値は緩やかに変動する。このため、本実施の形態において、ノイズ判定部１３は、低周波ノイズによる電圧値の変動を許容するため、抽出信号の振幅の中央値の変動量が所定の許容範囲内であれば、ノイズが発生していないと判定する。この所定の許容範囲を、本実施の形態ではノイズ許容範囲と称する。なお、低周波ノイズとは、抽出信号と比較して低周波であるノイズを意味している。 However, the amount of fluctuation in the voltage value of the extracted signal due to low-frequency noise is small (the amplitude waveform of the extracted signal does not collapse due to noise) and often does not hinder the determination of leakage by the leakage determination unit 14. When such low frequency noise occurs, the median value of the amplitude of the extracted signal varies gently. For this reason, in the present embodiment, the noise determination unit 13 allows the fluctuation of the voltage value due to the low frequency noise. Therefore, if the fluctuation amount of the median value of the extracted signal is within a predetermined allowable range, the noise is generated. It is determined that it has not occurred. This predetermined allowable range is referred to as a noise allowable range in the present embodiment. Note that the low frequency noise means noise having a lower frequency than the extracted signal.
　より詳細には、ノイズ判定部１３は、抽出信号の周期毎に、低周波ノイズによる電圧値の変動を許容するためのノイズ許容範囲を設定し、ある周期における抽出信号の振幅の中央値がノイズ許容範囲内である場合にはノイズが発生していないと判定する。すなわち、ノイズが全く発生していない場合、および、波形が崩れない程度の低周波ノイズが発生している場合には、抽出信号の振幅の中央値がノイズ許容範囲内となるので、ノイズ判定部１３は、ノイズが発生していないと判定する。この場合、漏電判定部１４は、抽出信号に基づいて漏電の有無を判定する。一方、ノイズ判定部１３は、当該周期における抽出信号の振幅の中央値がノイズ許容範囲外である場合には、ノイズが発生したと判定する。この場合、漏電判定部１４は、ノイズの影響による漏電の誤判定を防止するため、漏電の有無を判定しない。 More specifically, the noise determination unit 13 sets a noise allowable range for allowing a fluctuation in voltage value due to low frequency noise for each period of the extraction signal, and the median value of the amplitude of the extraction signal in a certain period is the noise If it is within the allowable range, it is determined that no noise is generated. That is, when no noise is generated or when low-frequency noise is generated to such an extent that the waveform does not collapse, the median value of the amplitude of the extracted signal is within the allowable noise range. 13 determines that no noise is generated. In this case, the leakage determination unit 14 determines the presence or absence of leakage based on the extracted signal. On the other hand, the noise determination unit 13 determines that noise has occurred when the median value of the amplitude of the extracted signal in the period is outside the allowable noise range. In this case, the leakage determination unit 14 does not determine the presence or absence of leakage in order to prevent erroneous determination of leakage due to the influence of noise.
　図３Ｂは、高周波ノイズが発生した場合の抽出信号の波形の一例を示す図である。図３Ｂに示すピークＰｎは、高周波ノイズにより電圧値が変動したピークである。このように短時間で急峻な電圧値の変動量を伴う（抽出信号の振幅の波形が崩れる）ノイズが発生した場合、漏電判定部１４は、実際には漏電が発生していないのに、漏電が発生したと誤判定してしまう可能性がある。このような高周波ノイズが発生した場合、抽出信号の振幅の中央値が大きく変動し、図３Ｂに示すように、その周期の抽出信号の振幅の中央値がノイズ許容範囲外に存在する。このため、このような電圧値の変動を検出した場合、ノイズ判定部１３は、ノイズが発生したと判定し、漏電判定部１４は、ノイズ判定部１３の判定に基づいて漏電の有無を判定しない。なお、高周波ノイズとは、検査信号と比較して高周波であるノイズを意味している。ノイズ許容範囲は、ノイズ判定部１３により抽出信号の一周期毎に設定される。 FIG. 3B is a diagram illustrating an example of a waveform of an extraction signal when high-frequency noise occurs. A peak Pn shown in FIG. 3B is a peak whose voltage value fluctuates due to high frequency noise. When noise with a steep voltage value variation (disruption of the amplitude waveform of the extracted signal) occurs in a short time in this manner, the leakage determination unit 14 determines that the leakage is not actually occurring even though the leakage has not actually occurred. It may be erroneously determined that the error occurred. When such high-frequency noise occurs, the median value of the amplitude of the extracted signal varies greatly, and as shown in FIG. For this reason, when such a change in voltage value is detected, the noise determination unit 13 determines that noise has occurred, and the leakage determination unit 14 does not determine whether there is a leakage based on the determination of the noise determination unit 13. . The high frequency noise means noise having a high frequency compared with the inspection signal. The allowable noise range is set for each cycle of the extracted signal by the noise determination unit 13.
　次に、漏電検出装置１０の動作例について説明する。図４は、漏電検出装置１０の動作例について説明するためのフローチャートである。 Next, an operation example of the leakage detection device 10 will be described. FIG. 4 is a flowchart for explaining an operation example of the leakage detection device 10.
　ステップＳ１において、ノイズ判定部１３は、抽出信号の一周期毎に、ノイズが発生しているか否かを判定する。この判定は、ある周期における抽出信号の振幅の中央値の変動量が、図３Ａ、図３Ｂに示すノイズ許容範囲内にあるか否かを判定することにより行う。より具体的には、ある周期における抽出信号の振幅の中央値をＶｃ、ノイズ検出用基準値をＶｃ＿ｓｔｄ、ノイズ検出用しきい値をＶｔｈｎとしたとき、ノイズ判定部１３は、以下の数式（１）が満たされる場合には抽出信号の電圧値の変動量がノイズ許容範囲内であるとし、ノイズが発生していないと判定する。そして、ノイズ判定部１３は、数式（１）が満たされない場合には、抽出信号の振幅の中央値の変動量がノイズ許容範囲外であるとし、ノイズが発生したと判定する。これらのパラメータの設定方法については、後に詳しく説明する。 In step S1, the noise determination unit 13 determines whether or not noise is generated for each cycle of the extracted signal. This determination is performed by determining whether or not the fluctuation amount of the median value of the amplitude of the extracted signal in a certain cycle is within the allowable noise range shown in FIGS. 3A and 3B. More specifically, when the median amplitude of the extracted signal in a certain cycle is Vc, the noise detection reference value is Vc_std, and the noise detection threshold value is Vthn, the noise determination unit 13 calculates the following formula (1 ) Is satisfied, it is determined that the fluctuation amount of the voltage value of the extracted signal is within the allowable noise range, and no noise is generated. And when the numerical formula (1) is not satisfied, the noise determination unit 13 determines that the amount of fluctuation in the median value of the amplitude of the extracted signal is outside the allowable noise range, and determines that noise has occurred. The method for setting these parameters will be described in detail later.
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000001
　換言すれば、数式（１）は、抽出信号の振幅の中央値Ｖｃがノイズ検出範囲Ｖｃ＿ｓｔｄ±Ｖｔｈｎ内にあるか否かを判定するための式である。 In other words, Expression (1) is an expression for determining whether or not the median value Vc of the amplitude of the extracted signal is within the noise detection range Vc_std ± Vthn.
　図４に示すように、ステップＳ１において、ノイズ判定部１３がノイズは発生していないと判定した場合、フローはステップＳ２に進む。一方、ステップＳ１において、ノイズが発生したとノイズ判定部１３が判定した場合、フローはステップＳ６に進む。 As shown in FIG. 4, when the noise determination unit 13 determines in step S1 that no noise is generated, the flow proceeds to step S2. On the other hand, if the noise determination unit 13 determines that noise has occurred in step S1, the flow proceeds to step S6.
　なお、上述したように、ステップＳ１におけるノイズ判定では、例えば図３Ａに例示したような低周波ノイズが発生していたとしても、ノイズが発生していると判定しない。そして、図３Ｂに例示するような短時間で急峻な波形の変化をもたらすノイズが発生していた場合に、ノイズが発生していると判定する。詳しくは後述するが、上記数式（１）のノイズ検出用しきい値Ｖｔｈｎは、図３Ａに例示するような低周波ノイズに起因する波形の変化よりも大きくなるように設定される。このため、ステップＳ１においては、低周波ノイズが発生している場合には、その低周波ノイズによる電圧値の変動がしきい値Ｖｔｈｎよりも小さくなるので、ノイズ判定部１３はノイズが発生していないと判定する。 Note that, as described above, in the noise determination in step S1, it is not determined that noise is generated even if low-frequency noise such as that illustrated in FIG. 3A is generated. Then, when noise that causes a steep waveform change in a short time as illustrated in FIG. 3B has occurred, it is determined that noise has occurred. As will be described in detail later, the noise detection threshold value Vthn in the above formula (1) is set to be larger than the change in waveform caused by the low frequency noise as illustrated in FIG. 3A. For this reason, in step S1, when low frequency noise is generated, the fluctuation of the voltage value due to the low frequency noise is smaller than the threshold value Vthn. Therefore, the noise determination unit 13 generates noise. Judge that there is no.
　ステップＳ１においてノイズが発生していないと判定された場合、ステップＳ２において、漏電判定部１４は、回路に漏電が発生しているか否かを判定する。漏電判定部１４による漏電の判定は、現在の周期における抽出信号の振幅が、図２Ｂに示すように、漏電が発生していない場合と比較して減衰しているか否かを検知することによって行う。具体的には、漏電判定部１４は、予め漏電（およびノイズ）が発生していない状態で高電圧回路１００および漏電検出装置１０を動作させ、抽出信号の振幅を予め取得してその値を保持しておき、漏電判定の際には、現在の周期における振幅を、予め取得した値と比較し、現在の周期の抽出信号の振幅と、漏電が発生していない場合の振幅との差が、漏電検出用しきい値Ｖｔｈｌ以上である場合に、漏電が発生していると判定する。ここで、漏電判定の判定基準となる、漏電検出用しきい値Ｖｔｈｌは、例えば高電圧回路１００において実験的に漏電を発生させた場合の抽出信号の電圧値等に基づいて、予め決定されればよい。 When it is determined in step S1 that no noise has occurred, in step S2, the leakage determination unit 14 determines whether or not a leakage has occurred in the circuit. The determination of leakage by the leakage determination unit 14 is performed by detecting whether or not the amplitude of the extracted signal in the current period is attenuated as compared to the case where no leakage has occurred, as shown in FIG. 2B. . Specifically, the leakage determination unit 14 operates the high-voltage circuit 100 and the leakage detection device 10 in a state where no leakage (and noise) has occurred in advance, acquires the amplitude of the extracted signal in advance, and holds that value. In addition, when determining leakage, the amplitude in the current cycle is compared with a value acquired in advance, and the difference between the amplitude of the extracted signal in the current cycle and the amplitude when no leakage has occurred, If it is equal to or greater than the leakage detection threshold value Vthl, it is determined that leakage has occurred. Here, the threshold value Vthl for leakage detection, which is a determination criterion for leakage detection, is determined in advance based on, for example, the voltage value of the extracted signal when leakage is experimentally generated in the high voltage circuit 100, for example. That's fine.
　ステップＳ２において、漏電判定部１４が漏電が発生していると判定した場合、フローはステップＳ３に進む。一方、ステップＳ２において、漏電が発生していないと漏電判定部１４が判定した場合、フローはステップＳ４に進む。 In step S2, if the leakage determination unit 14 determines that a leakage has occurred, the flow proceeds to step S3. On the other hand, if the leakage determination unit 14 determines in step S2 that no leakage has occurred, the flow proceeds to step S4.
　ステップＳ３において、漏電判定部１４は、漏電が発生しているとの判定結果を出力する。一方、ステップＳ４において、漏電判定部１４は漏電が発生していないとの判定結果を出力する。 In step S3, the leakage determination unit 14 outputs a determination result that leakage has occurred. On the other hand, in step S4, the leakage determination unit 14 outputs a determination result that leakage has not occurred.
　ステップＳ５において、ノイズ判定部１３は、ステップＳ３あるいはＳ４において判定結果を出力した後、現在の周期の振幅値等に基づいて、次の周期におけるノイズ検出用基準値Ｖｃ＿ｓｔｄを設定する。ノイズ検出用基準値Ｖｃ＿ｓｔｄの設定方法の詳細については後述する。 In step S5, the noise determination unit 13 outputs the determination result in step S3 or S4, and then sets the noise detection reference value Vc_std in the next period based on the amplitude value or the like of the current period. Details of the method of setting the noise detection reference value Vc_std will be described later.
　ステップＳ１において、ノイズが発生していると判定された場合、ステップＳ６において、漏電判定部１４は、現在の周期における漏電の有無を判定せず、前回の周期における漏電判定の結果を例えば車両の制御システム等に出力する。これにより、ノイズの影響で漏電の有無を判定できない場合でも、直近の漏電判定結果という、ある程度の信頼性がある漏電判定結果を出力することができる。そして、ステップＳ７において、現在の周期における処理を終え、次の周期に進む。 If it is determined in step S1 that noise has occurred, in step S6, the leakage determination unit 14 does not determine whether or not there is a leakage in the current cycle, and the result of the leakage determination in the previous cycle is, for example, the vehicle Output to the control system. Thereby, even when it is not possible to determine the presence or absence of leakage due to the influence of noise, it is possible to output a leakage determination result with a certain degree of reliability, that is, the latest leakage determination result. In step S7, the process in the current cycle is completed, and the process proceeds to the next cycle.
　以上、漏電検出装置１０の動作例について説明した。次に、図４に示すステップＳ１における各パラメータの設定方法について説明する。 The operation example of the leakage detection device 10 has been described above. Next, a method for setting each parameter in step S1 shown in FIG. 4 will be described.
　まず、低周波ノイズがない場合の抽出信号の振幅の中央値Ｖｃの算出方法の一例を図５Ａ～図５Ｃに示す。図５Ａは、低周波ノイズがない場合の、ある周期における中央値Ｖｃの算出方法について説明するための図である。上述したように、ノイズ判定部１３の動作は、図４に示すように抽出信号の１周期（漏電判定周期）毎に行われており、その周期における抽出信号の電圧値の最大値Ｖｍａｘと最小値Ｖｍｉｎとの中央値が現在の周期の中央値Ｖｃである。具体的には、中央値Ｖｃは以下の数式（２）を用いて算出される。 First, FIG. 5A to FIG. 5C show an example of a method for calculating the median value Vc of the amplitude of the extracted signal when there is no low frequency noise. FIG. 5A is a diagram for explaining a method of calculating the median value Vc in a certain cycle when there is no low frequency noise. As described above, the operation of the noise determination unit 13 is performed for each cycle (leakage determination cycle) of the extracted signal as shown in FIG. 4, and the maximum value Vmax and the minimum value of the voltage value of the extracted signal in that cycle. The median value with the value Vmin is the median value Vc of the current period. Specifically, the median value Vc is calculated using the following mathematical formula (2).
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000002
　低周波ノイズが発生している場合、図５Ｂあるいは図５Ｃに示すように、抽出信号の波形は低周波ノイズの影響により変動する。図５Ｂは、低周波ノイズの影響で、本来の振幅よりも抽出信号の振幅が小さく算出される場合を説明するための図である。また、図５Ｃは、低周波ノイズの影響で、本来の振幅よりも抽出信号の振幅が大きく算出される場合を説明するための図である。 When low frequency noise is generated, as shown in FIG. 5B or 5C, the waveform of the extracted signal varies due to the influence of the low frequency noise. FIG. 5B is a diagram for describing a case where the amplitude of the extracted signal is calculated to be smaller than the original amplitude due to the influence of low-frequency noise. FIG. 5C is a diagram for explaining a case where the amplitude of the extracted signal is calculated larger than the original amplitude due to the influence of low frequency noise.
　このように低周波ノイズの影響で抽出信号の波形が変動している場合、その抽出信号の振幅は本来の値とは異なる値となる。従って、低周波ノイズが発生している場合は、その影響を考慮した振幅に基づいた振幅中央値を算出する必要がある。 When the waveform of the extracted signal fluctuates due to the influence of low frequency noise as described above, the amplitude of the extracted signal is different from the original value. Therefore, when low frequency noise is generated, it is necessary to calculate the median amplitude based on the amplitude considering the influence.
　図６Ａおよび図６Ｂは、低周波ノイズの影響で抽出信号の波形が変動している場合の振幅中央値の算出方法を説明するための図である。図６Ａは、漏電判定周期の開始が抽出信号の増加タイミングである場合を示している。また、図６Ｂは、漏電判定周期の開始が抽出信号の減少タイミングである場合を示している。 6A and 6B are diagrams for explaining a calculation method of the median amplitude when the waveform of the extracted signal is fluctuated due to the influence of low frequency noise. FIG. 6A shows a case where the start of the leakage determination cycle is the increase timing of the extraction signal. FIG. 6B shows a case where the start of the leakage determination cycle is the extraction signal decrease timing.
　図６Ａおよび図６Ｂにおいて、Ｖｍａｘ＿ｔ０は、漏電判定周期ｔ０における最大値である。Ｖｍａｘ＿ｔ１は、漏電判定周期ｔ１における最大値である。また、Ｖｍｉｎ＿ｔ０は、漏電判定周期ｔ０における最小値である。Ｖｍｉｎ＿ｔ１は、漏電判定周期ｔ１における最小値である。また、ＶｍｉｎはＶｍｉｎ＿ｔ０とＶｍｉｎ＿ｔ１との中央値である。すなわち、Ｖｍｉｎは以下の数式（３）を用いて算出される。 6A and 6B, Vmax_t0 is the maximum value in the leakage determination cycle t0. Vmax_t1 is the maximum value in the leakage determination cycle t1. Vmin_t0 is the minimum value in the leakage determination cycle t0. Vmin_t1 is the minimum value in the leakage determination cycle t1. Vmin is the median value of Vmin_t0 and Vmin_t1. That is, Vmin is calculated using the following formula (3).
Figure JPOXMLDOC01-appb-M000003
Figure JPOXMLDOC01-appb-M000003
　図６Ａに示す場合、すなわち漏電判定周期の開始が抽出信号の増加タイミングである場合には、中央値Ｖｃは、以下の数式（４）を用いて算出される。 In the case shown in FIG. 6A, that is, when the start of the leakage determination cycle is the increase timing of the extracted signal, the median value Vc is calculated using the following formula (4).
Figure JPOXMLDOC01-appb-M000004
Figure JPOXMLDOC01-appb-M000004
　一方、図６Ｂに示す場合、すなわち漏電判定周期の開始が抽出信号の減少タイミングである場合には、中央値Ｖｃは、以下の数式（５）を用いて算出される。 On the other hand, in the case shown in FIG. 6B, that is, when the start of the leakage determination cycle is the decrease timing of the extracted signal, the median value Vc is calculated using the following formula (5).
Figure JPOXMLDOC01-appb-M000005
Figure JPOXMLDOC01-appb-M000005
　なお、上記Ｖｍａｘ、Ｖｍｉｎ、Ｖｍａｘ＿ｔ０、Ｖｍａｘ＿ｔ１、Ｖｍｉｎ＿ｔ０、Ｖｍｉｎ＿ｔ１の各パラメータは、例えば実測値を使用すればよい。 It should be noted that actual values may be used for the parameters Vmax, Vmin, Vmax_t0, Vmax_t1, Vmin_t0, and Vmin_t1, for example.
　次に、ノイズ検出用基準値Ｖｃ＿ｓｔｄの設定方法について説明する。ノイズ検出用基準値Ｖｃ＿ｓｔｄは、高電圧回路１００においてノイズ（あるいは漏電）が発生していない場合の抽出信号の振幅の中央値である。ノイズ検出用基準値Ｖｃ＿ｓｔｄの具体的な算出方法としては、例えば以下のような方法がある。 Next, a method for setting the noise detection reference value Vc_std will be described. The noise detection reference value Vc_std is the median value of the amplitude of the extracted signal when no noise (or leakage) occurs in the high voltage circuit 100. As a specific calculation method of the noise detection reference value Vc_std, for example, there is the following method.
　第１の方法として、例えばｎ周期目においてノイズが発生したと判定されなかった場合に、次周期ｎ＋１周期目のノイズ検出用基準値Ｖｃ＿ｓｔｄを、現在の周期であるｎ周期目の中央値Ｖｃに設定する方法がある。あるいは、第２の方法として、例えば過去数周期分における抽出信号の振幅の中央値を観測し、そのすべての周期においてノイズが発生していないと判定された場合に、当該数周期分の移動平均値を次周期におけるノイズ検出用基準値Ｖｃ＿ｓｔｄに設定する方法を採用してもよい。 As a first method, for example, when it is not determined that noise has occurred in the nth cycle, the noise detection reference value Vc_std in the next cycle n + 1 cycle is changed to the median value Vc in the nth cycle which is the current cycle. There is a way to set. Alternatively, as a second method, for example, when the median of the amplitude of the extracted signal in the past several cycles is observed and it is determined that no noise is generated in all the cycles, the moving average for the several cycles A method of setting the value to the noise detection reference value Vc_std in the next period may be adopted.
　このように、ノイズ検出用基準値Ｖｃ＿ｓｔｄは、抽出信号の周期毎に変更される。なお、ノイズ検出用基準値Ｖｃ＿ｓｔｄの初期値は、例えば、高電圧回路１００の設計上、ノイズ（あるいは漏電）が発生していない場合の理想的な抽出信号の振幅の中央値を算出し、その値を初期値として採用すればよい。あるいは、高電圧回路１００を構成する各部品（図示せず）によるばらつきを考慮して、高電圧回路１００および漏電検出装置１０の出荷時に、ノイズおよび漏電のない準理想的な環境で測定した抽出信号の実測値から取得した中央値をノイズ検出用基準値Ｖｃ＿ｓｔｄの初期値として設定してもよい。 Thus, the noise detection reference value Vc_std is changed for each cycle of the extracted signal. Note that the initial value of the noise detection reference value Vc_std is, for example, calculated as the median value of the amplitude of an ideal extracted signal when noise (or leakage) is not generated due to the design of the high voltage circuit 100. The value may be adopted as an initial value. Alternatively, in consideration of variation due to each component (not shown) constituting the high voltage circuit 100, the extraction was performed in a quasi-ideal environment free from noise and leakage when the high voltage circuit 100 and the leakage detection device 10 were shipped. The median value obtained from the actual measurement value of the signal may be set as the initial value of the noise detection reference value Vc_std.
　さらに、ノイズ検出用しきい値Ｖｔｈｎの設定方法について説明する。図７は、ノイズ検出用しきい値Ｖｔｈｎの設定方法について説明するための図である。図７において、点線の正弦曲線は低周波ノイズの波形を、実線の曲線は抽出信号の波形を、それぞれ示している。 Further, a method for setting the noise detection threshold value Vthn will be described. FIG. 7 is a diagram for explaining a method of setting the noise detection threshold value Vthn. In FIG. 7, the dotted sine curve indicates the waveform of the low frequency noise, and the solid curve indicates the waveform of the extracted signal.
　図７に示すように、抽出信号の波形は、低周波ノイズの影響により変動している。ノイズ検出用しきい値Ｖｔｈｎは、電圧測定範囲を超えない範囲の最大の低周波ノイズによる抽出信号への影響を許容できるように設定される。具体的には、図７において、抽出信号の振幅をＶａｍｐ、電圧測定範囲をＶｒａｎｇｅ、抽出信号の周期をｔ、低周波ノイズの周期をＴとすると、低周波ノイズの振幅は（Ｖｒａｎｇｅ－Ｖａｍｐ）であることから、抽出信号１周期分で許容できる振幅変動量であるノイズ検出用しきい値Ｖｔｈｎは、以下の数式（６）のように算出される。 As shown in FIG. 7, the waveform of the extracted signal fluctuates due to the influence of low frequency noise. The noise detection threshold value Vthn is set so as to allow the influence on the extracted signal by the maximum low-frequency noise within a range not exceeding the voltage measurement range. Specifically, in FIG. 7, when the amplitude of the extracted signal is Vamp, the voltage measurement range is Vrange, the period of the extracted signal is t, and the period of the low frequency noise is T, the amplitude of the low frequency noise is (Vrange-Vamp). Therefore, the threshold value Vthn for noise detection, which is the amount of amplitude fluctuation that can be allowed for one cycle of the extracted signal, is calculated as in the following formula (6).
Figure JPOXMLDOC01-appb-M000006
Figure JPOXMLDOC01-appb-M000006
　なお、以上説明したノイズ検出用しきい値Ｖｔｈｎの設定方法は一例であり、本発明はこれに限定されない。一般に、ノイズ検出用しきい値Ｖｔｈｎは、低周波ノイズによる抽出信号の変動をある程度許容するような値に設定されればよい。 The above-described method for setting the threshold value Vthn for noise detection is an example, and the present invention is not limited to this. In general, the noise detection threshold value Vthn may be set to a value that allows some variation in the extracted signal due to low-frequency noise.
　以上説明したように、本発明の実施の形態に係る漏電検出装置１０は、信号出力部１１と、信号抽出部１２と、漏電判定部１４と、を有する。信号出力部１１は、高電圧回路１００へ検出抵抗Ｒ０およびカップリングコンデンサＣ０を介して検査信号を出力する。信号抽出部１２は、検出抵抗Ｒ０とカップリングコンデンサＣ０との間の結節点ｎ１における検査信号を調整し、抽出信号を出力する。漏電判定部１４は、この抽出信号の振幅に基づいて高電圧回路１００の漏電を検知する。漏電判定部１４は、抽出信号の現在の周期における振幅の中央値と、抽出信号の過去の周期における振幅の中央値に基づいて設定される基準値との差分が許容範囲内にある場合に現在の周期における振幅に基づいた漏電検出結果を出力する。また、この差分が許容範囲外にある場合に現在の周期における振幅に基づいた有効な漏電検出結果を出力しない。 As described above, the leakage detection device 10 according to the embodiment of the present invention includes the signal output unit 11, the signal extraction unit 12, and the leakage determination unit 14. The signal output unit 11 outputs a test signal to the high voltage circuit 100 via the detection resistor R0 and the coupling capacitor C0. The signal extraction unit 12 adjusts the inspection signal at the node n1 between the detection resistor R0 and the coupling capacitor C0, and outputs an extraction signal. The leakage determination unit 14 detects leakage of the high voltage circuit 100 based on the amplitude of the extracted signal. The leakage determination unit 14 presents the current value when the difference between the median amplitude of the extracted signal in the current cycle and the reference value set based on the median amplitude of the extracted signal in the past cycle is within an allowable range. The leakage detection result based on the amplitude in the period is output. Further, when this difference is outside the allowable range, an effective leakage detection result based on the amplitude in the current cycle is not output.
　このような構成により、抽出信号の振幅の中央値との差分を算出するための基準値を固定値ではなく、抽出信号の過去の周期における振幅の中央値としている。このため、周期が短く波形の変動量が大きいノイズ（例えば、高周波ノイズ）が発生した場合には、差分が所定の許容範囲（ノイズ許容範囲）外となる。一方、周期が長く波形の変動量が短いノイズ（例えば、低周波ノイズ）が発生した場合には、差分が所定の許容範囲内となる。このため、低周波ノイズが発生した場合でも、ノイズ判定部１３はノイズが発生したと判定せず、漏電判定部１４が漏電の有無を判定することができる。 With such a configuration, the reference value for calculating the difference from the median amplitude of the extracted signal is not a fixed value, but the median amplitude of the extracted signal in the past cycle. For this reason, when noise (for example, high-frequency noise) having a short period and a large waveform fluctuation amount occurs, the difference is outside a predetermined allowable range (noise allowable range). On the other hand, when noise (for example, low frequency noise) having a long period and a short waveform variation occurs, the difference is within a predetermined allowable range. For this reason, even when low frequency noise occurs, the noise determination unit 13 does not determine that noise has occurred, and the leakage determination unit 14 can determine whether there is leakage.
　さらに、漏電判定部１４は、ノイズが発生したとノイズ判定部１３が判定した場合に、現在の周期における漏電判定の結果として、前回の周期における漏電判定の結果を維持する。このため、例えば高周波ノイズが発生した場合等に漏電判定が行われなかった場合も、的確な漏電判定結果を得ることができる。 Furthermore, when the noise determination unit 13 determines that noise has occurred, the leakage determination unit 14 maintains the result of the leakage determination in the previous cycle as the result of the leakage determination in the current cycle. For this reason, an accurate leakage determination result can be obtained even when the leakage determination is not performed, for example, when high-frequency noise occurs.
　なお、ノイズが発生したとノイズ判定部１３が判定した場合（抽出信号の現在の周期における振幅の中央値と、抽出信号の過去の周期における振幅の中央値に基づいて設定される基準値との差分が所定の許容範囲内にない場合）、漏電判定部１４は、現在の周期における漏電の有無を判定しないと説明したが、これに限らず、現在の周期における漏電の有無を判定しても良い。 Note that, when the noise determination unit 13 determines that noise has occurred (a median value of the amplitude of the extracted signal in the current cycle and a reference value set based on the median value of the amplitude of the extracted signal in the past cycle) In the case where the difference is not within a predetermined allowable range), the leakage determining unit 14 has been described as not determining whether or not there is a leakage in the current cycle. good.
　この場合、現在の周期における漏電判定結果は誤判定の可能性があるため、現在の周期における漏電判定結果を出力しない（例えば、漏電判定結果そのものを出力しない、あるいは、前回の周期における漏電検出の結果を出力する）、あるいは、現在の周期における漏電判定結果を出力する場合であれば、フラグ等により漏電判定結果が有効でない（誤検知の可能性がある）旨も合わせて出力することが好ましい。 In this case, since the leakage determination result in the current cycle may be erroneously determined, the leakage determination result in the current cycle is not output (for example, the leakage determination result itself is not output or the leakage detection result in the previous cycle is not detected). Output the result), or if the leakage determination result in the current cycle is output, it is preferable to output that the leakage determination result is not valid (possibly with a false detection) due to a flag or the like. .
　すなわち、ノイズが発生したとノイズ判定部１３が判定した場合（抽出信号の現在の周期における振幅の中央値と、抽出信号の過去の周期における振幅の中央値に基づいて設定される基準値との差分が所定の許容範囲内にない場合）、漏電判定部１４は、現在の周期における振幅に基づいた有効な漏電検出結果を出力しない。 That is, when the noise determination unit 13 determines that noise has occurred (the median amplitude of the extracted signal in the current cycle and the reference value set based on the median amplitude of the extracted signal in the past cycle) When the difference is not within the predetermined allowable range), the leakage determination unit 14 does not output an effective leakage detection result based on the amplitude in the current cycle.
　本発明は、例えば車両に搭載される高電圧回路の漏電を検出する漏電検出装置に適用することができる。 The present invention can be applied to a leakage detection device that detects a leakage of a high voltage circuit mounted on a vehicle, for example.
１０　　漏電検出装置
１１　　信号出力部
１２　　信号抽出部
１３　　ノイズ判定部
１４　　漏電判定部
１００　　高電圧回路
１１０　　電池
１１１　　絶縁抵抗
１２０　　負荷
Ｃ０　　カップリングコンデンサ DESCRIPTION OF SYMBOLS 10 Leakage detection apparatus 11 Signal output part 12 Signal extraction part 13 Noise determination part 14 Leakage determination part 100 High voltage circuit 110 Battery 111 Insulation resistance 120 Load C0 Coupling capacitor

Claims (8)

  1. 検出抵抗と、結節点において前記検出抵抗と直列に接続されたカップリングコンデンサとを介して検査信号を高電圧回路へ出力する信号出力部と、
    前記結節点における前記検査信号を調整し、抽出信号を出力する信号抽出部と、
    前記抽出信号の振幅に基づいて前記高電圧回路の漏電を検知する漏電判定部と、を備え、
    前記漏電判定部は、
    前記抽出信号の現在の周期における振幅の中央値と、前記抽出信号の過去の周期における振幅の中央値に基づいて設定される基準値との差分が許容範囲内にある場合に前記現在の周期における振幅に基づいた漏電検出結果を出力し、
    前記差分が前記許容範囲外にある場合に前記現在の周期における振幅に基づいた有効な漏電検出結果を出力しない、
    漏電検出装置。     A signal output unit that outputs a test signal to a high-voltage circuit via a detection resistor and a coupling capacitor connected in series with the detection resistor at a node;
    A signal extraction unit that adjusts the inspection signal at the node and outputs an extraction signal;
    A leakage determining unit that detects a leakage of the high-voltage circuit based on the amplitude of the extracted signal, and
    The leakage determination unit
    When the difference between the median amplitude in the current cycle of the extracted signal and a reference value set based on the median amplitude in the past cycle of the extracted signal is within an allowable range, Output the leakage detection result based on the amplitude,
    When the difference is outside the allowable range, do not output an effective leakage detection result based on the amplitude in the current period,
    Earth leakage detection device.
  2. 前記差分が前記許容範囲内にある場合にノイズが発生していないと判定し、前記差分が前記許容範囲外である場合にノイズが発生したと判定するノイズ判定部をさらに備えた、
    請求項１に記載の漏電検出装置。     A noise determination unit that determines that no noise has occurred when the difference is within the allowable range, and that has determined that noise has occurred when the difference is outside the allowable range;
    The leakage detection device according to claim 1.
  3. 前記許容範囲は、低周波ノイズによる抽出信号の波形変動を許容する範囲である、
    請求項１または２に記載の漏電検出装置。     The allowable range is a range that allows the waveform fluctuation of the extraction signal due to low frequency noise,
    The leakage detection device according to claim 1 or 2.
  4. 前記漏電判定部は、前記差分が前記許容範囲外である場合に、前記現在の周期における漏電検出結果として、前回の周期における漏電検出結果を維持する、
    請求項１または２に記載の漏電検出装置。     The leakage detection unit maintains the leakage detection result in the previous cycle as the leakage detection result in the current cycle when the difference is outside the allowable range.
    The leakage detection device according to claim 1 or 2.
  5. 前記差分が前記許容範囲内である場合に、次周期における基準値は、前記現在の周期における抽出信号の振幅の中央値である、
    請求項１または２に記載の漏電検出装置。     When the difference is within the allowable range, the reference value in the next period is the median value of the amplitude of the extracted signal in the current period.
    The leakage detection device according to claim 1 or 2.
  6. 前記差分が前記許容範囲内である場合に、次周期における基準値は、前記現在の周期より過去の所定数の周期における抽出信号の振幅の中央値の移動平均値である、
    請求項１または２に記載の漏電検出装置。     When the difference is within the allowable range, the reference value in the next cycle is a moving average value of the median value of the amplitudes of the extracted signals in a predetermined number of cycles past the current cycle.
    The leakage detection device according to claim 1 or 2.
  7. 前記差分が前記許容範囲外である場合に、次周期における基準値は、前記現在の周期と同一の前記基準値である、
    請求項１または２に記載の漏電検出装置。     When the difference is outside the allowable range, the reference value in the next period is the same reference value as the current period.
    The leakage detection device according to claim 1 or 2.
  8. 高電圧回路へ検出抵抗およびカップリングコンデンサを介して検査信号を出力するステップと、
    前記検出抵抗と前記カップリングコンデンサとの間の結節点における前記検査信号を調整し、抽出信号を出力するステップと、
    前記抽出信号の振幅に基づいて前記高電圧回路の漏電を検知するステップと、を備え、
    前記高電圧回路の漏電を検知するステップは、
    前記抽出信号の現在の周期における振幅の中央値と、前記抽出信号の過去の周期における振幅の中央値に基づいて設定される基準値との差分が許容範囲内にあるか否かを判定するステップと、
    前記差分が前記許容範囲内にあると判定された場合に前記現在の周期における振幅に基づいた漏電検出結果を出力し、前記差分が前記許容範囲外にあると判定された場合に前記現在の周期における振幅に基づいた有効な漏電検出結果を出力しないステップと、を有する、
    漏電検出方法。     Outputting a test signal to the high voltage circuit via a detection resistor and a coupling capacitor;
    Adjusting the inspection signal at a node between the detection resistor and the coupling capacitor, and outputting an extraction signal;
    Detecting leakage of the high-voltage circuit based on the amplitude of the extracted signal,
    The step of detecting leakage of the high voltage circuit comprises:
    Determining whether or not a difference between a median amplitude of the extracted signal in a current cycle and a reference value set based on a median amplitude of the extracted signal in a past cycle is within an allowable range. When,
    When it is determined that the difference is within the allowable range, a leakage detection result based on the amplitude in the current cycle is output, and when the difference is determined to be outside the allowable range, the current cycle is output. Not outputting an effective leakage detection result based on the amplitude in
    Electric leakage detection method.
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