WO2019176173A1 - Electricity leakage detection circuit and vehicle power supply system - Google Patents

Electricity leakage detection circuit and vehicle power supply system Download PDF

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WO2019176173A1
WO2019176173A1 PCT/JP2018/042376 JP2018042376W WO2019176173A1 WO 2019176173 A1 WO2019176173 A1 WO 2019176173A1 JP 2018042376 W JP2018042376 W JP 2018042376W WO 2019176173 A1 WO2019176173 A1 WO 2019176173A1
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voltage
leakage
leakage detection
detection
cells
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PCT/JP2018/042376
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French (fr)
Japanese (ja)
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田中 康晴
矢野 準也
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三洋電機株式会社
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Publication of WO2019176173A1 publication Critical patent/WO2019176173A1/en

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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/50Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
    • G01R31/52Testing for short-circuits, leakage current or ground faults
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/42Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/48Accumulators combined with arrangements for measuring, testing or indicating condition, e.g. level or density of the electrolyte
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02HEMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/16Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to fault current to earth, frame or mass
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10Energy storage using batteries

Abstract

To highly accurately estimate an electricity leakage resistance value, when a current for electricity leakage detection flows through a resistor (15/16) for electricity leakage detection, a voltage detection unit (12) for electricity leakage detection detects the end-to-end voltage of the resistor (15/16) for electricity leakage detection as a voltage for electricity leakage detection. A processing unit (11) acquires the total voltage of a plurality of cells (21–2n) from a voltage detection unit (50) for cell voltage detection that is for detecting the voltages of each of the plurality of cells (21–2n) and acquires the voltage for electricity leakage detection from the voltage detection unit (12) for electricity leakage detection. The time constant for the total voltage input to the processing unit (11) from the voltage detection unit (50) for cell voltage detection is fixed. The time constant for the voltage for electricity leakage detection input to the processing unit (11) from the voltage detection unit (12) for electricity leakage detection varies according to an electricity leakage resistance (5/6). The processing unit (11) applies a filter (11a) to the total voltage so as to match the time constant of the total voltage to the time constant of the voltage for electricity leakage detection.

Description

漏電検出回路、車両用電源システムElectric leakage detection circuit, vehicle power supply system
 本発明は、高電圧の蓄電部とシャーシアース間の漏電を検出する漏電検出回路、車両用電源システムに関する。 The present invention relates to a leakage detection circuit and a vehicle power supply system for detecting a leakage between a high-voltage power storage unit and a chassis ground.
 近年、HEV (Hybrid Electric Vehicle)、PHV(Plug-in Hybrid Vehicle)、EV(Electric Vehicle)の出荷台数が増えてきている。これらの車両には、補機電池(一般的に12V出力の鉛電池)と別に駆動用電池が搭載される。駆動用電池は高電圧であるため、感電を防止するために、駆動用電池と車両のボディ(シャーシアース)間は直接接続されず、両者の間にはYコンデンサが挿入される。また駆動用電池とシャーシアース間の絶縁抵抗を監視して漏電を検出する漏電検出回路が搭載される。 In recent years, shipments of HEV (Hybrid Electric Vehicle), PHV (Plug-in Hybrid Vehicle) and EV (Electric Vehicle) are increasing. In these vehicles, a driving battery is mounted separately from an auxiliary battery (generally a lead battery of 12V output). Since the driving battery has a high voltage, in order to prevent an electric shock, the driving battery and the vehicle body (chassis ground) are not directly connected, and a Y capacitor is inserted between them. In addition, a leakage detection circuit that monitors the insulation resistance between the driving battery and the chassis ground to detect leakage is mounted.
 直流電流を用いた漏電検出方式では、漏電検出用の抵抗に漏電検出用の電流を流し、当該抵抗の両端電圧である漏電検出用の電圧と、駆動用電池の電圧との関係から漏電抵抗値を推定する(例えば、特許文献1参照)。 In the leakage detection method using a direct current, a leakage detection current is passed through the leakage detection resistor, and the leakage resistance value is calculated from the relationship between the leakage detection voltage, which is the voltage across the resistor, and the voltage of the drive battery. (See, for example, Patent Document 1).
特開2014-81267号公報JP 2014-81267 A
 駆動用電池と走行用モータ間に流れる電流は、急発進や急ブレーキなどにより大きく変動する。駆動用電池の充放電電流が大きく変動すると駆動用電池の電圧もその影響により変動する。漏電抵抗の検出中に駆動用電池の電圧が急変すると、漏電検出用の電圧と駆動用電池の電圧との比が崩れ、漏電抵抗値の推定にノイズが混入しやすくなる。 The current flowing between the driving battery and the traveling motor varies greatly due to sudden start or braking. When the charging / discharging current of the driving battery greatly varies, the voltage of the driving battery also varies due to the influence. If the voltage of the driving battery suddenly changes during the detection of the leakage resistance, the ratio between the leakage detection voltage and the driving battery voltage collapses, and noise is likely to be mixed in the estimation of the leakage resistance value.
 本発明はこうした状況に鑑みなされたものであり、その目的は、漏電抵抗値を高精度に推定する技術を提供することにある。 The present invention has been made in view of such a situation, and an object thereof is to provide a technique for estimating a leakage resistance value with high accuracy.
 上記課題を解決するために、本発明のある態様の漏電検出回路は、直列接続された複数のセルとシャーシアース間に漏電検出用の抵抗を介して漏電検出用の電流が流れると、前記漏電検出用の抵抗の両端電圧を漏電検出用の電圧として検出する漏電検出用の電圧検出部と、前記複数のセルの各セルの電圧を検出するためのセル電圧検出用の電圧検出部から前記複数のセルの総電圧を取得し、前記漏電検出用の電圧検出部から前記漏電検出用の電圧を取得し、取得した前記総電圧と前記漏電検出用の電圧をもとに、前記複数のセルと前記シャーシアース間の漏電抵抗値を推定する処理部と、を備える。前記複数のセルと前記シャーシアースはコンデンサを介して接続されており、前記セル電圧検出用の電圧検出部から前記処理部に入力される前記総電圧の時定数は固定であり、前記漏電検出用の電圧検出部から前記処理部に入力される前記漏電検出用の電圧の時定数は漏電抵抗に応じて可変であり、前記処理部は、前記漏電検出用の電圧の時定数に前記総電圧の時定数を対応させるために前記総電圧にフィルタを適用し、当該フィルタを適用した後の前記総電圧と、前記漏電検出用の電圧をもとに前記漏電抵抗値を推定する。 In order to solve the above-described problem, the leakage detection circuit according to an aspect of the present invention is configured such that a leakage detection current flows between a plurality of cells connected in series and a chassis ground via a leakage detection resistor. The voltage detection unit for detecting a leakage current that detects the voltage across the detection resistor as a voltage for leakage detection, and the plurality of voltage detection units for detecting the voltage of each cell of the plurality of cells. The leakage detection voltage from the leakage detection voltage detector, and based on the acquired leakage voltage and the leakage detection voltage, the plurality of cells And a processing unit for estimating a leakage resistance value between the chassis grounds. The plurality of cells and the chassis ground are connected via a capacitor, and the time constant of the total voltage input from the voltage detection unit for detecting the cell voltage to the processing unit is fixed, and for detecting the leakage The time constant of the leakage detection voltage input from the voltage detection unit to the processing unit is variable according to a leakage resistance, and the processing unit sets the time constant of the total voltage to the time constant of the leakage detection voltage. In order to correspond to the time constant, a filter is applied to the total voltage, and the leakage resistance value is estimated based on the total voltage after the filter is applied and the leakage detection voltage.
 本発明によれば、漏電抵抗値を高精度に推定することができる。 According to the present invention, the leakage resistance value can be estimated with high accuracy.
本発明の実施の形態に係る電源システムを説明するための図である。It is a figure for demonstrating the power supply system which concerns on embodiment of this invention. 漏電検出回路の基本動作を説明するための図である。It is a figure for demonstrating the basic operation | movement of a leak detection circuit. 図3(a)、(b)は、漏電検出処理中の総電圧と漏電検出用電圧の波形推移の一例を示す図である。FIGS. 3A and 3B are diagrams illustrating examples of waveform transitions of the total voltage and the leakage detection voltage during the leakage detection process. 総電圧と漏電検出用電圧の比の関係の一例を示す図である。It is a figure which shows an example of the relationship of the ratio of a total voltage and the voltage for a leak detection. 実施例1に係る電圧検出部及び処理部の構成例を示す図である。FIG. 3 is a diagram illustrating a configuration example of a voltage detection unit and a processing unit according to the first embodiment. 漏電検出用電圧の入力波形の一例を示す図である。It is a figure which shows an example of the input waveform of the voltage for electric leakage detection. 図7(a)、(b)は、処理部のIIRフィルタの具体例を説明するための図である。FIGS. 7A and 7B are diagrams for explaining a specific example of the IIR filter of the processing unit. 実施例2に係る電圧検出部及び処理部の構成例を示す図である。FIG. 6 is a diagram illustrating a configuration example of a voltage detection unit and a processing unit according to a second embodiment. 実施例2に係る漏電検出回路の処理の流れを示すフローチャートである。6 is a flowchart illustrating a flow of processing of a leakage detection circuit according to a second embodiment. 図10(a)-(c)は、漏電抵抗値の変化が漏電検出用電圧の入力波形の収束時間に与える影響を説明するための図である。FIGS. 10A to 10C are diagrams for explaining the influence of the change in the leakage resistance value on the convergence time of the input waveform of the leakage detection voltage. フィルタ係数が正しく算出できている場合の漏電検出用電圧の入力波形の一例を示す図である。It is a figure which shows an example of the input waveform of the voltage for earth-leakage detection when a filter coefficient is correctly calculated. 図12(a)、(b)は、漏電検出処理中の総電圧と漏電検出用電圧の波形推移の一例を示す図である。FIGS. 12A and 12B are diagrams illustrating examples of waveform transitions of the total voltage and the leakage detection voltage during the leakage detection process.
 図1は、本発明の実施の形態に係る電源システム1を説明するための図である。電源システム1は、車両の駆動用電池として車両に搭載されて使用される。電源システム1は、直列接続された複数のセル21-2nを含む。セルには、リチウムイオン電池セル、ニッケル水素電池セル、鉛電池セル、電気二重層キャパシタセル、リチウムイオンキャパシタセル等を用いることができる。以下、本明細書ではリチウムイオン電池セル(公称電圧:3.6-3.7V)を使用する例を想定する。 FIG. 1 is a diagram for explaining a power supply system 1 according to an embodiment of the present invention. The power supply system 1 is mounted on a vehicle and used as a vehicle driving battery. Power supply system 1 includes a plurality of cells 21-2n connected in series. As the cell, a lithium ion battery cell, a nickel metal hydride battery cell, a lead battery cell, an electric double layer capacitor cell, a lithium ion capacitor cell, or the like can be used. Hereinafter, in this specification, an example in which a lithium ion battery cell (nominal voltage: 3.6-3.7 V) is used is assumed.
 電源システム1の正極端子71と負極端子72は、走行用モータを駆動するためのインバータに接続される。力行時、電源システム1はインバータを介して走行用モータに放電し、回生時、電源システム1は走行用モータにより発電された電力をインバータを介して充電する。また車両がPHV/EVの場合、電源システム1の正極端子71と負極端子72は充電ケーブルを介して、車両の外部に設置された充電器と接続することができ、外部の充電器から充電することができる。 The positive terminal 71 and the negative terminal 72 of the power supply system 1 are connected to an inverter for driving the traveling motor. During power running, the power supply system 1 discharges to the traveling motor via the inverter, and during regeneration, the power supply system 1 charges the electric power generated by the traveling motor via the inverter. When the vehicle is PHV / EV, the positive terminal 71 and the negative terminal 72 of the power supply system 1 can be connected to a charger installed outside the vehicle via a charging cable, and charging is performed from the external charger. be able to.
 電源システム1の正極端子71に接続された高圧ラインと車両のシャーシアース2間は第1コンデンサ3を介して接続され、電源システム1の負極端子72に接続された低圧ラインと車両のシャーシアース2間は第2コンデンサ4を介して接続される。電源システム1と第1コンデンサ3間に遮断スイッチ61が接続され、電源システム1と第2コンデンサ4間に遮断スイッチ62が接続され、電源システム1とシャーシアース2間を電気的に切り離すことができる。 The high-voltage line connected to the positive terminal 71 of the power supply system 1 and the chassis ground 2 of the vehicle are connected via the first capacitor 3, and the low-voltage line connected to the negative terminal 72 of the power supply system 1 and the chassis ground 2 of the vehicle. They are connected via a second capacitor 4. A cutoff switch 61 is connected between the power supply system 1 and the first capacitor 3, and a cutoff switch 62 is connected between the power supply system 1 and the second capacitor 4, so that the power supply system 1 and the chassis ground 2 can be electrically disconnected. .
 電源システム1は、複数のセル21-2nの各セルの電圧を検出するための電圧検出部50を備える。電圧検出部50は、直列接続された複数のセル21-2nの各ノードと複数の電圧検出線で接続され、隣接する電圧検出線間の電圧を検出して各セル21-2nの電圧を検出する。電圧検出部50は、検出した複数のセル21-2nの各電圧を加算して複数のセル21-2nの総電圧Vtを算出する。電圧検出部50は算出した複数のセル21-2nの総電圧Vtを処理部11に出力する。電圧検出部50は例えば、アナログフロントエンドICまたはASIC(Application Specific Integrated Circuit)で構成することができる。電圧検出部50は処理部11に対して高圧であるため、電圧検出部50と処理部11間は絶縁された状態で、通信線で接続される。 The power supply system 1 includes a voltage detection unit 50 for detecting the voltage of each of the plurality of cells 21-2n. The voltage detection unit 50 is connected to each node of a plurality of cells 21-2n connected in series by a plurality of voltage detection lines, and detects a voltage between adjacent voltage detection lines to detect a voltage of each cell 21-2n. To do. The voltage detector 50 adds the detected voltages of the plurality of cells 21-2n to calculate the total voltage Vt of the plurality of cells 21-2n. The voltage detection unit 50 outputs the calculated total voltage Vt of the plurality of cells 21-2n to the processing unit 11. The voltage detection unit 50 can be configured by, for example, an analog front end IC or an ASIC (Application Specific Integrated Circuit). Since the voltage detection unit 50 has a high voltage with respect to the processing unit 11, the voltage detection unit 50 and the processing unit 11 are connected by a communication line in an insulated state.
 複数のセル21-2nと電圧検出部50間を接続する複数の電圧検出線にそれぞれ抵抗31-3nが挿入され、隣接する2本の電圧検出線間にそれぞれコンデンサ41-4mが接続される。複数の抵抗31-3n及びコンデンサ41-4mはローパスフィルタ(RCフィルタ)を構成する。当該ローパスフィルタはエイリアシングを抑制する作用を有する。 A resistor 31-3n is inserted into each of the plurality of voltage detection lines connecting the plurality of cells 21-2n and the voltage detection unit 50, and a capacitor 41-4m is connected between each of the two adjacent voltage detection lines. The plurality of resistors 31-3n and the capacitor 41-4m constitute a low pass filter (RC filter). The low-pass filter has an effect of suppressing aliasing.
 電源システム1は漏電検出回路10を備える。漏電検出回路10は処理部11、差動アンプ12、A/D変換器13、第1電流制限抵抗14、第1スイッチ18、第1漏電検出用抵抗15、第2漏電検出用抵抗16、第2スイッチ19及び第2電流制限抵抗17を備える。 The power supply system 1 includes a leakage detection circuit 10. The leakage detection circuit 10 includes a processing unit 11, a differential amplifier 12, an A / D converter 13, a first current limiting resistor 14, a first switch 18, a first leakage detection resistor 15, a second leakage detection resistor 16, a first Two switches 19 and a second current limiting resistor 17 are provided.
 電源システム1の高圧ラインと低圧ライン間に、第1電流制限抵抗14、第1スイッチ18、第1漏電検出用抵抗15、第2漏電検出用抵抗16、第2スイッチ19及び第2電流制限抵抗17が直列に接続される。第1漏電検出用抵抗15と第2漏電検出用抵抗16間の接続点がシャーシアース2に接続される。 Between the high-voltage line and the low-voltage line of the power supply system 1, the first current limiting resistor 14, the first switch 18, the first leakage detection resistor 15, the second leakage detection resistor 16, the second switch 19, and the second current limiting resistor 17 are connected in series. A connection point between the first leakage detection resistor 15 and the second leakage detection resistor 16 is connected to the chassis ground 2.
 第1漏電検出用抵抗15及び第2漏電検出用抵抗16の両端に、差動アンプ12の2入力端子がそれぞれ接続される。差動アンプ12は第1漏電検出用抵抗15及び第2漏電検出用抵抗16の両端電圧を増幅してA/D変換器13に出力する。A/D変換器13は、差動アンプ12から入力されるアナログ電圧をデジタル値に変換して処理部11に出力する。なお、A/D変換器13は処理部11に内蔵されていてもよい。 The two input terminals of the differential amplifier 12 are respectively connected to both ends of the first leakage detection resistor 15 and the second leakage detection resistor 16. The differential amplifier 12 amplifies the voltage across the first leakage detection resistor 15 and the second leakage detection resistor 16 and outputs the amplified voltage to the A / D converter 13. The A / D converter 13 converts the analog voltage input from the differential amplifier 12 into a digital value and outputs the digital value to the processing unit 11. The A / D converter 13 may be built in the processing unit 11.
 第1電流制限抵抗14及び第2電流制限抵抗17には、例えば100kΩ以上の抵抗値を持つ高抵抗素子が用いられる。第1漏電検出用抵抗15及び第2漏電検出用抵抗16には、例えば10kΩ未満の、第1電流制限抵抗14及び第2電流制限抵抗17より相対的に抵抗値が小さい抵抗素子が使用される。漏電検出用の電流は、微弱な電流に設定される。 For the first current limiting resistor 14 and the second current limiting resistor 17, for example, high resistance elements having a resistance value of 100 kΩ or more are used. For the first leakage detection resistor 15 and the second leakage detection resistor 16, a resistance element having a resistance value relatively smaller than that of the first current limiting resistor 14 and the second current limiting resistor 17, for example, less than 10 kΩ is used. . The current for leakage detection is set to a weak current.
 第1スイッチ18は、第1電流制限抵抗14と第1漏電検出用抵抗15の間に挿入される。第2スイッチ19は,第2漏電検出用抵抗16と第2電流制限抵抗17の間に挿入される。第1スイッチ18及び第2スイッチ19は、リレー(例えば、フォトMOSリレー)や半導体スイッチ(例えば、MOSFET、IGBT)で構成することができる。第1スイッチ18及び第2スイッチ19は、原則的に相補的にオン/オフする。 The first switch 18 is inserted between the first current limiting resistor 14 and the first leakage detection resistor 15. The second switch 19 is inserted between the second leakage detection resistor 16 and the second current limiting resistor 17. The 1st switch 18 and the 2nd switch 19 can be comprised by a relay (for example, photoMOS relay) and a semiconductor switch (for example, MOSFET, IGBT). The first switch 18 and the second switch 19 are turned on / off in a complementary manner in principle.
 処理部11は、電圧検出部50から入力される複数のセル21-2nの総電圧Vtと、A/D変換器13を介して差動アンプ12から入力される漏電検出用電圧Vgをもとに、複数のセル21-2nとシャーシアース2間の漏電抵抗値を推定する。処理部11は例えば、マイクロコンピュータ及び不揮発メモリ(例えば、EEPROM、フラッシュメモリ)により構成することができる。 The processing unit 11 is based on the total voltage Vt of the plurality of cells 21-2n input from the voltage detection unit 50 and the leakage detection voltage Vg input from the differential amplifier 12 via the A / D converter 13. In addition, the leakage resistance value between the plurality of cells 21-2n and the chassis ground 2 is estimated. The processing unit 11 can be configured by, for example, a microcomputer and a nonvolatile memory (for example, EEPROM, flash memory).
 図2は、漏電検出回路10の基本動作を説明するための図である。処理部11は第2スイッチ19をターンオフする。この状態(t1)では、第1電流制限抵抗14→第1漏電検出用抵抗15→第2漏電抵抗6という経路で複数のセル21-2nの正極からシャーシアース2を介し複数のセル21-2nの負極を介してシャーシアース2に漏電検出用の電流が流れる。流れる電流は、第2漏電抵抗6の抵抗値に応じて変動する。処理部11は第2スイッチ19をターンオフしてから所定時間後(図2に示す例では5.0秒後)のタイミングで、電圧検出部50から入力される総電圧Vt(t1)と、差動アンプ12から入力される漏電検出用電圧Vg(t1)を取得する(サンプリングする)。 FIG. 2 is a diagram for explaining the basic operation of the leakage detection circuit 10. The processing unit 11 turns off the second switch 19. In this state (t1), the plurality of cells 21-2n are connected from the positive electrodes of the plurality of cells 21-2n through the chassis ground 2 through the path of the first current limiting resistor 14, the first leakage detection resistor 15, and the second leakage resistor 6. A current for detecting a leakage flows through the chassis ground 2 through the negative electrode. The flowing current varies according to the resistance value of the second leakage resistance 6. The processing unit 11 differs from the total voltage Vt (t1) input from the voltage detection unit 50 at a timing after a predetermined time (5.0 seconds in the example shown in FIG. 2) after the second switch 19 is turned off. The leakage detection voltage Vg (t1) input from the dynamic amplifier 12 is acquired (sampled).
 その後、処理部11は第1スイッチ18をターンオフ及び第2スイッチ19をターンオンする。この状態(t2)では、第1漏電抵抗5→第2漏電検出用抵抗16→第2電流制限抵抗17という経路で複数のセル21-2nの正極からシャーシアース2を介し複数のセル21-2nの負極に漏電検出用の電流が流れる。流れる電流は、第1漏電抵抗5の抵抗値に応じて変動する。処理部11は第1スイッチ18をターンオフ及び第2スイッチ19をターンオンしてから所定時間後(図2に示す例では5.0秒後)のタイミングで、電圧検出部50から入力される総電圧Vt(t2)と、差動アンプ12から入力される漏電検出用電圧Vg(t2)を取得する。 Thereafter, the processing unit 11 turns off the first switch 18 and turns on the second switch 19. In this state (t2), the plurality of cells 21-2n are connected from the positive electrodes of the plurality of cells 21-2n through the chassis ground 2 through the path of the first leakage resistance 5 → second leakage detection resistance 16 → second current limiting resistance 17. Current for leakage detection flows through the negative electrode. The flowing current varies according to the resistance value of the first leakage resistance 5. The processing unit 11 is a total voltage input from the voltage detection unit 50 at a timing after a predetermined time (5.0 seconds in the example shown in FIG. 2) after the first switch 18 is turned off and the second switch 19 is turned on. Vt (t2) and the leakage detection voltage Vg (t2) input from the differential amplifier 12 are acquired.
 処理部11は、下記(式1)をもとに第1漏電抵抗5と第2漏電抵抗6の合成抵抗値Rを算出することができる。
 R=Ra/(x+y)-(Ra+Rb) ・・・(式1)
 ここで、
 Raは第1漏電検出用抵抗15/第2漏電検出用抵抗16の抵抗値
 Rbは第1電流制限抵抗14/第2電流制限抵抗17の抵抗値
 x=Vg(t1)/Vt(t1)
 y=Vg(t2)/Vt(t2)
The processing unit 11 can calculate a combined resistance value RL of the first leakage resistance 5 and the second leakage resistance 6 based on the following (Equation 1).
R L = Ra / (x + y) − (Ra + Rb) (Formula 1)
here,
Ra is the resistance value of the first leakage detection resistor 15 / second leakage detection resistor 16 Rb is the resistance value of the first current limiting resistor 14 / second current limiting resistor 17 x = Vg (t1) / Vt (t1)
y = Vg (t2) / Vt (t2)
 処理部11は、下記(式2)、(式3)をもとに第1漏電抵抗5の抵抗値R1と第2漏電抵抗6の抵抗値R2を算出する。
 R1=(1+x/y)・R=Ra/y-(1+x/y)・(Ra+Rb) ・・・(式2)
 R2=(1+y/x)・R=Ra/x-(1+y/x)・(Ra+Rb) ・・・(式3)
The processing unit 11 calculates the resistance value R1 of the first leakage resistance 5 and the resistance value R2 of the second leakage resistance 6 based on the following (Expression 2) and (Expression 3).
R1 = (1 + x / y) · R L = Ra / y− (1 + x / y) · (Ra + Rb) (Formula 2)
R2 = (1 + y / x) · R L = Ra / x− (1 + y / x) · (Ra + Rb) (Formula 3)
 処理部11は、算出した第1漏電抵抗5の抵抗値R1または第2漏電抵抗6の抵抗値R2が漏電検出用の閾値を下回ると、複数のセル21-2nからシャーシアース2に漏電していると判定する。 When the calculated resistance value R1 of the first leakage resistance 5 or the calculated resistance value R2 of the second leakage resistance 6 falls below the threshold value for detecting leakage, the processing unit 11 leaks from the plurality of cells 21-2n to the chassis ground 2. It is determined that
 漏電検出用電圧Vgの測定中に複数のセル21-2nの総電圧Vtが変化すると、規定時間内に波形が安定せず、正しい漏電抵抗値R1、R2を測定することが困難になる。即ち、漏電検出用電圧Vgの測定中に総電圧Vtが変動すると、漏電抵抗値R1、R2の検出精度が低下する。 If the total voltage Vt of the plurality of cells 21-2n changes during the measurement of the leakage detection voltage Vg, the waveform is not stabilized within the specified time, and it is difficult to measure the correct leakage resistance values R1 and R2. That is, if the total voltage Vt fluctuates during the measurement of the leakage detection voltage Vg, the detection accuracy of the leakage resistance values R1 and R2 decreases.
 図3(a)、(b)は、漏電検出処理中の総電圧Vtと漏電検出用電圧Vgの波形推移の一例を示す図である。図3(a)は、漏電検出処理中に総電圧Vtが変動しない例を示しており、図3(b)は、漏電検出処理中に総電圧Vtが変動する例を示している。図3(a)に示す例では、処理部11が総電圧Vtと漏電検出用電圧Vgを取得する時点で、漏電検出用電圧Vgの波形が収束済みで安定している。従って高精度な漏電抵抗値R1、R2を検出することができる。一方、図3(b)に示す例では、処理部11が総電圧Vtと漏電検出用電圧Vgを取得する時点で、総電圧Vtの波形は収束しているが漏電検出用電圧Vgの波形は収束していない。漏電検出用電圧Vgの波形は、第1コンデンサ3及び第2コンデンサ4の影響により収束が遅れる。従って漏電抵抗値R1、R2の検出精度が低くなる。 FIGS. 3A and 3B are diagrams showing examples of waveform transitions of the total voltage Vt and the leakage detection voltage Vg during the leakage detection process. FIG. 3A illustrates an example in which the total voltage Vt does not vary during the leakage detection process, and FIG. 3B illustrates an example in which the total voltage Vt varies during the leakage detection process. In the example shown in FIG. 3A, when the processing unit 11 acquires the total voltage Vt and the leakage detection voltage Vg, the waveform of the leakage detection voltage Vg is converged and stable. Therefore, it is possible to detect the leakage resistance values R1 and R2 with high accuracy. On the other hand, in the example shown in FIG. 3B, when the processing unit 11 acquires the total voltage Vt and the leakage detection voltage Vg, the waveform of the total voltage Vt is converged, but the waveform of the leakage detection voltage Vg is It has not converged. The convergence of the waveform of the leakage detection voltage Vg is delayed due to the influence of the first capacitor 3 and the second capacitor 4. Accordingly, the detection accuracy of the leakage resistance values R1 and R2 is lowered.
 図3(b)に示すように総電圧Vtの時定数τtと漏電検出用電圧Vgの時定数τgが一致しないと、総電圧Vtと漏電検出用電圧Vgの比の関係が崩れる。両者の比の関係が崩れると、上記(式1)-(式3)の変数x、yの精度が低下し、漏電抵抗値R1、R2の検出精度が低下する。総電圧Vtの時定数τtと漏電検出用電圧Vgの時定数τgが一致していれば、総電圧Vtと漏電検出用電圧Vgの比の関係は保たれる。 As shown in FIG. 3B, if the time constant τt of the total voltage Vt does not match the time constant τg of the leakage detection voltage Vg, the relationship between the ratio of the total voltage Vt and the leakage detection voltage Vg is broken. If the relationship between the two ratios is broken, the accuracy of the variables x and y in the above (formula 1) to (formula 3) is lowered, and the detection accuracy of the leakage resistance values R1 and R2 is lowered. If the time constant τt of the total voltage Vt matches the time constant τg of the leakage detection voltage Vg, the relationship between the ratio of the total voltage Vt and the leakage detection voltage Vg is maintained.
 図4は、総電圧Vtと漏電検出用電圧Vgの比の関係の一例を示す図である。総電圧Vtの時定数τtと漏電検出用電圧Vgの時定数τgが一致していれば、どの時点においても両者の波形収束度が一致することになる。上記(式1)の変数xは下記(式4)に示すように常に同じ値になる。変数yについても同様である。
 x=Vg(ta)/Vt(ta)=Vg(tb)/Vt(tb)=Vg(tc)/Vt(tc)=Vg(td)/Vt(td) ・・・(式4)
FIG. 4 is a diagram illustrating an example of the relationship between the ratio between the total voltage Vt and the leakage detection voltage Vg. If the time constant τt of the total voltage Vt and the time constant τg of the leakage detection voltage Vg coincide with each other, the waveform convergence degree of both coincides at any time. The variable x in the above (Expression 1) always has the same value as shown in the following (Expression 4). The same applies to the variable y.
x = Vg (ta) / Vt (ta) = Vg (tb) / Vt (tb) = Vg (tc) / Vt (tc) = Vg (td) / Vt (td) (Formula 4)
 そこで本実施の形態では、総電圧Vtの時定数τtと漏電検出用電圧Vgの時定数τgを一致させるための仕組みを導入する。具体的には総電圧Vtの時定数τtが、漏電検出用電圧Vgの時定数τgに一致するように、総電圧Vtにフィルタをかける。漏電検出用電圧Vgの時定数τgは、漏電検出処理中の漏電検出用電圧Vgの収束波形から予測する方法と、過去に算出した漏電抵抗値から推定する方法が考えられる。前者の方法を実施例1で説明し、後者の方法を実施例2で説明する。 Therefore, in this embodiment, a mechanism for matching the time constant τt of the total voltage Vt with the time constant τg of the leakage detection voltage Vg is introduced. Specifically, the total voltage Vt is filtered so that the time constant τt of the total voltage Vt matches the time constant τg of the leakage detection voltage Vg. The time constant τg of the leakage detection voltage Vg can be estimated from a convergence waveform of the leakage detection voltage Vg during the leakage detection process, or can be estimated from a leakage resistance value calculated in the past. The former method is described in Example 1, and the latter method is described in Example 2.
 図5は、実施例1に係る電圧検出部50及び処理部11の構成例を示す図である。電圧検出部50は、マルチプレクサ50a、A/D変換器50b、セル電圧加算部50c及びIIRフィルタ50dを含む。処理部11は、IIRフィルタ11a、漏電抵抗推定部11b及び時定数予測部11cを含む。 FIG. 5 is a diagram illustrating a configuration example of the voltage detection unit 50 and the processing unit 11 according to the first embodiment. The voltage detection unit 50 includes a multiplexer 50a, an A / D converter 50b, a cell voltage addition unit 50c, and an IIR filter 50d. The processing unit 11 includes an IIR filter 11a, a leakage resistance estimation unit 11b, and a time constant prediction unit 11c.
 電圧検出部50においてマルチプレクサ50aは、隣接する2本の電圧検出線間の電圧を順番にA/D変換器50bに出力する。A/D変換器50bは、マルチプレクサ50aから入力されるアナログ電圧をデジタル値に変換してセル電圧加算部50cに出力する。セル電圧加算部50cは全セル21~2nの電圧を加算して総電圧を算出する。IIR(Infinite Impulse Response)フィルタ50dは、セル電圧加算部50cから入力される総電圧にフィルタ演算を実行し、フィルタ演算後の総電圧Vtを処理部11に送信する。 In the voltage detection unit 50, the multiplexer 50a sequentially outputs the voltage between two adjacent voltage detection lines to the A / D converter 50b. The A / D converter 50b converts the analog voltage input from the multiplexer 50a into a digital value and outputs the digital value to the cell voltage adder 50c. The cell voltage adder 50c calculates the total voltage by adding the voltages of all the cells 21 to 2n. An IIR (Infinite Impulse Response) filter 50d performs a filter operation on the total voltage input from the cell voltage adding unit 50c, and transmits the total voltage Vt after the filter operation to the processing unit 11.
 電圧検出部50の前段のRCフィルタ(図1参照)の抵抗とコンデンサの定数、及びIIRフィルタ50dのフィルタ係数、カットオフ周波数は固定である。また設計者に既知の値である。従って、電圧検出部50から処理部11に入力される総電圧Vtの時定数τtは既知の固定値となる。 The resistance and capacitor constants of the RC filter (see FIG. 1) in the previous stage of the voltage detection unit 50, the filter coefficient of the IIR filter 50d, and the cutoff frequency are fixed. The value is known to the designer. Therefore, the time constant τt of the total voltage Vt input from the voltage detection unit 50 to the processing unit 11 is a known fixed value.
 漏電検出用電圧Vgの時定数τgは、第1漏電検出用抵抗15/第2漏電検出用抵抗16の抵抗値Ra、第1電流制限抵抗14/第2電流制限抵抗17の抵抗値Rb、第1漏電抵抗5の抵抗値R1、第2漏電抵抗6の抵抗値R2、第1コンデンサ3の容量値C1及び第2コンデンサ4の容量値C2に依存する。即ち、漏電検出用電圧Vgの時定数τgは下記(式5)により算出できる。
 τg=((Ra+Rb)//R1//R2)・(C1+C2) ・・・(式5)
The time constant τg of the leakage detection voltage Vg includes the resistance value Ra of the first leakage detection resistor 15 / second leakage detection resistor 16, the resistance value Rb of the first current limiting resistor 14 / second current limiting resistor 17, the first It depends on the resistance value R1 of the first leakage resistance 5, the resistance value R2 of the second leakage resistance 6, the capacitance value C1 of the first capacitor 3, and the capacitance value C2 of the second capacitor 4. That is, the time constant τg of the leakage detection voltage Vg can be calculated by the following (formula 5).
τg = ((Ra + Rb) // R1 // R2). (C1 + C2) (Formula 5)
 この内、第1漏電検出用抵抗15/第2漏電検出用抵抗16の抵抗値Ra、第1電流制限抵抗14/第2電流制限抵抗17の抵抗値Rb、第1コンデンサ3の容量値C1及び第2コンデンサ4の容量値C2が既知の固定値であり、第1漏電抵抗5の抵抗値R1及び第2漏電抵抗6の抵抗値R2が未知の変動値である。 Among these, the resistance value Ra of the first leakage detection resistor 15 / second leakage detection resistor 16, the resistance value Rb of the first current limiting resistor 14 / second current limiting resistor 17, the capacitance value C1 of the first capacitor 3, and The capacitance value C2 of the second capacitor 4 is a known fixed value, and the resistance value R1 of the first leakage resistor 5 and the resistance value R2 of the second leakage resistor 6 are unknown fluctuation values.
 実施例1では漏電検出用電圧Vgの時定数τgを、漏電検出用電圧Vgの入力波形の3点を測定することにより予測する。即ち、漏電検出用電圧Vgの変化量からフィードフォワード方式で、時定数τgを予測する。 In Example 1, the time constant τg of the leakage detection voltage Vg is predicted by measuring three points of the input waveform of the leakage detection voltage Vg. That is, the time constant τg is predicted by the feedforward method from the amount of change in the leakage detection voltage Vg.
 図6は、漏電検出用電圧Vgの入力波形の一例を示す図である。処理部11の時定数予測部11cは、下記(式6)をもとに漏電検出用電圧Vgの時定数τg[s]を算出する。なお時刻t1-t2間、時刻t2-t3間は等間隔である。
 τg=log0.368((Vt3-Vt2)/(Vt2-Vt1))・(t2-t1) ・・・(式6)
 0.368は、1/e(eは自然対数)を示す。
FIG. 6 is a diagram illustrating an example of an input waveform of the leakage detection voltage Vg. The time constant prediction unit 11c of the processing unit 11 calculates the time constant τg [s] of the leakage detection voltage Vg based on the following (formula 6). Note that there is an equal interval between times t1 and t2 and between times t2 and t3.
τg = log 0.368 ((Vt3-Vt2) / (Vt2-Vt1)) · (t2-t1) (Expression 6)
0.368 indicates 1 / e (e is a natural logarithm).
 時定数予測部11cは、他の3点の計測電圧をもとに他の時定数τgを算出し、複数の時定数τgの平均値を算出してもよい。時定数予測部11cは、予測した漏電検出用電圧Vgの時定数τgをIIRフィルタ11aに供給する。 The time constant prediction unit 11c may calculate another time constant τg based on the other three measurement voltages, and may calculate an average value of the plurality of time constants τg. The time constant prediction unit 11c supplies the predicted time constant τg of the leakage detection voltage Vg to the IIR filter 11a.
 IIRフィルタ11aは、時定数予測部11cから供給される時定数τgをもとにカットオフ周波数Fcを算出し、算出したカットオフ周波数Fcをもとにフィルタ係数kを決定する。IIRフィルタ11aは、決定したフィルタ係数kをもとに電圧検出部50から入力される総電圧Vtにフィルタ演算を実行して、フィルタ演算後の総電圧Vt’を算出する。以下、具体例を挙げて説明する。 The IIR filter 11a calculates the cutoff frequency Fc based on the time constant τg supplied from the time constant prediction unit 11c, and determines the filter coefficient k based on the calculated cutoff frequency Fc. The IIR filter 11a performs a filter operation on the total voltage Vt input from the voltage detection unit 50 based on the determined filter coefficient k, and calculates a total voltage Vt ′ after the filter operation. Hereinafter, a specific example will be described.
 図7(a)、(b)は、処理部11のIIRフィルタ11aの具体例を説明するための図である。図7(a)は、カットオフ周波数Fcからフィルタ係数kを導出するための関数の一例を示し、図7(b)は、第1漏電抵抗5と第2漏電抵抗6の合成抵抗値R(=R1//R2)、漏電検出用電圧Vgの時定数τg、カットオフ周波数Fc、及び収束時間の関係の一例を示す。なお収束時間は、漏電検出用電圧Vgの入力波形が99.9%に収束するまでの時間を示している。なお本具体例では、電圧検出部50から処理部11に入力される総電圧Vtの時定数τtは約30ms(5.3Hz)とする。 FIGS. 7A and 7B are diagrams for describing a specific example of the IIR filter 11a of the processing unit 11. FIG. FIG. 7A shows an example of a function for deriving the filter coefficient k from the cutoff frequency Fc, and FIG. 7B shows a combined resistance value R L of the first leakage resistance 5 and the second leakage resistance 6. (= R1 / R2), an example of the relationship between the time constant τg of the leakage detection voltage Vg, the cutoff frequency Fc, and the convergence time is shown. The convergence time indicates the time until the input waveform of the leakage detection voltage Vg converges to 99.9%. In this specific example, the time constant τt of the total voltage Vt input from the voltage detection unit 50 to the processing unit 11 is about 30 ms (5.3 Hz).
 第1漏電抵抗5と第2漏電抵抗6の合成抵抗値R(=R1//R2)は、時定数τgが決まると上記(式5)をもとに算出することができる。またカットオフ周波数Fcは、時定数τが決まると下記(式7)をもとに算出することができる。
 Fc=1/2πτ ・・・(式7)
The combined resistance value R L (= R1 // R2) of the first leakage resistance 5 and the second leakage resistance 6 can be calculated based on the above (formula 5) when the time constant τg is determined. The cut-off frequency Fc can be calculated based on the following (Equation 7) when the time constant τ is determined.
Fc = 1 / 2πτ (Expression 7)
 フィルタ係数kは、既知の総電圧Vtのカットオフ周波数5.3Hzを、上記(式6)で算出される漏電検出用電圧Vgのカットオフ周波数Fcに変換する際に使用するIIRフィルタ11aのフィルタ係数である。フィルタ係数kは、合成抵抗値R1∥R2、すなわち漏電検出用電圧Vgのカットオフ周波数Fcが決まると一意的に決まる値であり、合成抵抗値R1∥R2毎に予め算出することができる。算出したフィルタ係数kを図7(b)に示す。また、カットオフ周波数Fcとフィルタ係数kの複数の組から近似関数が導出される。例えば、本具体例では下記(式8)に示す近似関数が導出される。
 k=Round(4.2758*ln(Fc)+7.4632) ・・・(式8)
The filter coefficient k is the filter of the IIR filter 11a used when converting the cutoff frequency 5.3 Hz of the known total voltage Vt to the cutoff frequency Fc of the leakage detection voltage Vg calculated by the above (formula 6). It is a coefficient. The filter coefficient k is a value uniquely determined when the combined resistance value R1∥R2, that is, the cutoff frequency Fc of the leakage detection voltage Vg is determined, and can be calculated in advance for each combined resistance value R1∥R2. The calculated filter coefficient k is shown in FIG. An approximate function is derived from a plurality of sets of the cutoff frequency Fc and the filter coefficient k. For example, in this specific example, the approximate function shown in (Expression 8) below is derived.
k = Round (4.2758 * ln (Fc) +7.4632) (Equation 8)
 本具体例で使用するIIRフィルタ11aは、下記(式9)に定義される。
 Y(n)=k/16*X(n)+(1-k/16)*Y(n-1) ・・・(式9)
The IIR filter 11a used in this specific example is defined by the following (formula 9).
Y (n) = k / 16 * X (n) + (1-k / 16) * Y (n-1) (Formula 9)
 IIRフィルタ11aは、フィルタ演算後の総電圧Vt’を漏電抵抗推定部11bに出力する。漏電抵抗推定部11bは、時刻t1の総電圧Vt’(t1)及び漏電検出用電圧Vg(t1)と、時刻t2の総電圧Vt’(t2)及び漏電検出用電圧Vg(t2)を上記(式1)-(式3)に代入して、第1漏電抵抗5の抵抗値R1及び第2漏電抵抗6の抵抗値R2を算出する。漏電抵抗推定部11bは、算出した第1漏電抵抗5の抵抗値R1または第2漏電抵抗6の抵抗値R2が漏電検出用の閾値を下回ると、漏電発生を上位のECU(Electronic Control Unit)に通知する。 The IIR filter 11a outputs the total voltage Vt ′ after the filter calculation to the leakage resistance estimation unit 11b. The leakage resistance estimation unit 11b obtains the total voltage Vt ′ (t1) and the leakage detection voltage Vg (t1) at time t1, the total voltage Vt ′ (t2) and the leakage detection voltage Vg (t2) at time t2 as described above ( The resistance value R1 of the first leakage resistance 5 and the resistance value R2 of the second leakage resistance 6 are calculated by substituting into the expressions (1) to (3). When the calculated resistance value R1 of the first earth leakage resistance 5 or the resistance value R2 of the second earth leakage resistance 6 falls below the threshold value for detecting earth leakage, the earth leakage resistance estimating unit 11b sends the occurrence of earth leakage to a higher ECU (Electronic Control Unit). Notice.
 図8は、実施例2に係る電圧検出部50及び処理部11の構成例を示す図である。電圧検出部50の構成は、図5に示した実施例1に係る電圧検出部50の構成と同じである。処理部11は、IIRフィルタ11a、漏電抵抗推定部11b及び信頼性判定部11dを含む。実施例2では時定数予測部11cは設けられない。 FIG. 8 is a diagram illustrating a configuration example of the voltage detection unit 50 and the processing unit 11 according to the second embodiment. The configuration of the voltage detection unit 50 is the same as the configuration of the voltage detection unit 50 according to the first embodiment illustrated in FIG. The processing unit 11 includes an IIR filter 11a, a leakage resistance estimation unit 11b, and a reliability determination unit 11d. In the second embodiment, the time constant prediction unit 11c is not provided.
 実施例2では、過去に算出した第1漏電抵抗5と第2漏電抵抗6の合成抵抗値R(=R1//R2)をもとに漏電検出用電圧Vgの時定数τgを算出する。即ち、フィードバック方式で時定数τgを決定する。 In Example 2, the time constant τg of the leakage detection voltage Vg is calculated based on the combined resistance value R L (= R1 // R2) of the first leakage resistance 5 and the second leakage resistance 6 calculated in the past. That is, the time constant τg is determined by a feedback method.
 図9は、実施例2に係る漏電検出回路10の処理の流れを示すフローチャートである。漏電抵抗推定部11bは、IIRフィルタ11aにフィルタ係数kを設定する(S10)。フィルタ係数kの初期値は例えば、1である。漏電抵抗推定部11bは、図示しないスイッチ駆動部に制御信号を供給して、第1スイッチ18をオン及び第2スイッチ19をオフに制御する(S11)。 FIG. 9 is a flowchart illustrating a processing flow of the leakage detection circuit 10 according to the second embodiment. The earth leakage resistance estimation unit 11b sets the filter coefficient k in the IIR filter 11a (S10). The initial value of the filter coefficient k is, for example, 1. The earth leakage resistance estimation unit 11b supplies a control signal to a switch driving unit (not shown) to control the first switch 18 on and the second switch 19 off (S11).
 処理部11は、電圧検出部50から総電圧Vt(t1)を取得してIIRフィルタ11aに供給し、差動アンプ12から漏電検出用電圧Vg(t1)を取得して漏電抵抗推定部11bに供給する(S12)。IIRフィルタ11aは、総電圧Vt(t1)にフィルタ演算を実行し、漏電検出用電圧Vgと時定数τが実質的に一致した総電圧Vt’(t1)を算出する(S13)。IIRフィルタ11aは、フィルタ演算後の総電圧Vt’(t1)を漏電抵抗推定部11bに供給する。 The processing unit 11 acquires the total voltage Vt (t1) from the voltage detection unit 50 and supplies it to the IIR filter 11a, acquires the leakage detection voltage Vg (t1) from the differential amplifier 12, and supplies it to the leakage resistance estimation unit 11b. Supply (S12). The IIR filter 11a performs a filter operation on the total voltage Vt (t1), and calculates a total voltage Vt ′ (t1) in which the leakage detection voltage Vg substantially matches the time constant τ (S13). The IIR filter 11a supplies the total voltage Vt ′ (t1) after the filter calculation to the leakage resistance estimation unit 11b.
 漏電抵抗推定部11bは、図示しないスイッチ駆動部に制御信号を供給して、第1スイッチ18をオフ及び第2スイッチ19をオンに制御する(S14)。処理部11は、電圧検出部50から総電圧Vt(t2)を取得してIIRフィルタ11aに供給し、差動アンプ12から漏電検出用電圧Vg(t2)を取得して漏電抵抗推定部11bに供給する(S15)。IIRフィルタ11aは、総電圧Vt(t2)にフィルタ演算を実行し、漏電検出用電圧Vgと時定数τが実質的に一致した総電圧Vt’(t2)を算出する(S16)。IIRフィルタ11aは、フィルタ演算後の総電圧Vt’(t2)を漏電抵抗推定部11bに供給する。 The earth leakage resistance estimation unit 11b supplies a control signal to a switch driving unit (not shown) to control the first switch 18 to be off and the second switch 19 to be on (S14). The processing unit 11 acquires the total voltage Vt (t2) from the voltage detection unit 50 and supplies it to the IIR filter 11a, acquires the leakage detection voltage Vg (t2) from the differential amplifier 12, and supplies it to the leakage resistance estimation unit 11b. Supply (S15). The IIR filter 11a performs a filter operation on the total voltage Vt (t2), and calculates a total voltage Vt ′ (t2) in which the leakage detection voltage Vg substantially matches the time constant τ (S16). The IIR filter 11a supplies the total voltage Vt ′ (t2) after the filter calculation to the leakage resistance estimation unit 11b.
 漏電抵抗推定部11bは、時刻t1の総電圧Vt’(t1)及び漏電検出用電圧Vg(t1)と、時刻t2の総電圧Vt’(t2)及び漏電検出用電圧Vg(t2)を上記(式1)-(式3)に代入して、漏電抵抗値R1、R2を算出する(S17)。漏電抵抗推定部11bは、漏電抵抗値R1、R2を上記(式5)に代入して漏電検出用電圧Vgの時定数τgを算出する(S18)。漏電抵抗推定部11bは、時定数τgを上記(式7)に代入してカットオフ周波数Fcを算出し、算出したカットオフ周波数Fcを上記(式8)に代入してIIRフィルタ11aのフィルタ係数kを算出する(S19)。漏電検出処理が継続している間(S20のN)はステップS10に遷移し、漏電抵抗推定部11bは、算出したフィルタ係数kを新たなフィルタ係数kとして、IIRフィルタ11aに設定する(S10)。 The leakage resistance estimation unit 11b obtains the total voltage Vt ′ (t1) and the leakage detection voltage Vg (t1) at time t1, the total voltage Vt ′ (t2) and the leakage detection voltage Vg (t2) at time t2 as described above ( Substituting into Equations 1) to 3 to calculate leakage resistance values R1 and R2 (S17). The leakage resistance estimation unit 11b calculates the time constant τg of the leakage detection voltage Vg by substituting the leakage resistance values R1 and R2 into the above (formula 5) (S18). The earth leakage resistance estimation unit 11b calculates the cut-off frequency Fc by substituting the time constant τg into the above (Equation 7), and substitutes the calculated cut-off frequency Fc into the above (Equation 8) to obtain the filter coefficient of the IIR filter 11a. k is calculated (S19). While the leakage detection process continues (N in S20), the process proceeds to step S10, and the leakage resistance estimation unit 11b sets the calculated filter coefficient k as a new filter coefficient k in the IIR filter 11a (S10). .
 実施例2に係るフィードバック方式では、漏電抵抗値R1、R2が急変した場合、その急変にIIRフィルタ11aが追従しきれない場合が発生する。そこで実施例2では信頼性判定部11dを追加している。 In the feedback method according to the second embodiment, when the leakage resistance values R1 and R2 change suddenly, the IIR filter 11a may not be able to follow the sudden change. Therefore, in the second embodiment, a reliability determination unit 11d is added.
 図10(a)-(c)は、漏電抵抗値R1、R2の変化が漏電検出用電圧Vgの入力波形の収束時間に与える影響を説明するための図である。この例は、図7(b)に示した関係を前提としている。図10(a)は第1漏電抵抗5と第2漏電抵抗6の合成抵抗値R(=R1//R2)が1000kΩの場合の漏電検出用電圧Vgの入力波形を示している。図10(b)は合成抵抗値R(=R1//R2)が500kΩの場合の漏電検出用電圧Vgの入力波形を示している。図10(c)は合成抵抗値R(=R1//R2)が100kΩの場合の漏電検出用電圧Vgの入力波形を示している。 FIGS. 10A to 10C are diagrams for explaining the influence of changes in leakage resistance values R1 and R2 on the convergence time of the input waveform of leakage detection voltage Vg. This example is based on the relationship shown in FIG. FIG. 10A shows an input waveform of the leakage detection voltage Vg when the combined resistance value R L (= R1 // R2) of the first leakage resistance 5 and the second leakage resistance 6 is 1000 kΩ. FIG. 10B shows an input waveform of the leakage detection voltage Vg when the combined resistance value R L (= R1 // R2) is 500 kΩ. FIG. 10C shows an input waveform of the leakage detection voltage Vg when the combined resistance value R L (= R1 // R2) is 100 kΩ.
 図10(a)に示す1000kΩの場合のフィルタ係数kは4であり、収束時間は2.7sである。図10(b)に示す500kΩの場合のフィルタ係数kは5であり、収束時間は1.7sである。図10(c)に示す100kΩの場合のフィルタ係数kは11であり、収束時間は0.4sである。このように第1漏電抵抗5と第2漏電抵抗6の合成抵抗値R(=R1//R2)が小さくなるほど、収束時間が短くなる。 In the case of 1000 kΩ shown in FIG. 10A, the filter coefficient k is 4, and the convergence time is 2.7 s. In the case of 500 kΩ shown in FIG. 10B, the filter coefficient k is 5, and the convergence time is 1.7 s. In the case of 100 kΩ shown in FIG. 10C, the filter coefficient k is 11, and the convergence time is 0.4 s. Thus, the convergence time becomes shorter as the combined resistance value R L (= R1 // R2) of the first leakage resistance 5 and the second leakage resistance 6 becomes smaller.
 図11は、フィルタ係数kが正しく算出できている場合の漏電検出用電圧Vgの入力波形の一例を示す図である。フィルタ係数kが正しく算出できている場合、時定数τgから算出できる波形収束点(n-7)以降において、総電圧Vt’と漏電検出用電圧Vgの比が一定となる。即ち、上記(式1)の変数xは下記(式10)に示すように常に同じ値になる。変数yについても同様である。
 x=Vg(n-7)/Vt’(n-7)=Vg(n-6)/Vt’(n-6)= ・・・ =Vg(n)/Vt’(n) ・・・(式10)
FIG. 11 is a diagram illustrating an example of an input waveform of the leakage detection voltage Vg when the filter coefficient k is correctly calculated. When the filter coefficient k is correctly calculated, the ratio between the total voltage Vt ′ and the leakage detection voltage Vg is constant after the waveform convergence point (n−7) that can be calculated from the time constant τg. That is, the variable x in the above (Expression 1) always has the same value as shown in the following (Expression 10). The same applies to the variable y.
x = Vg (n−7) / Vt ′ (n−7) = Vg (n−6) / Vt ′ (n−6) =... = Vg (n) / Vt ′ (n) ( Formula 10)
 信頼性判定部11dは、収束期間中の総電圧Vt’と漏電検出用電圧Vgの比が実質的に一定でない場合、誤ったフィルタ係数kがIIRフィルタ11aに設定されたと判定し、そのフィルタ係数kが設定されたIIRフィルタ11aにより算出された総電圧Vt’に基づく漏電抵抗値R1、R2を無効と判定する。収束期間中の総電圧Vt’と漏電検出用電圧Vgの比が実質的に一定であるか否かは、例えば、前値との差分が所定値以下であるか否かにより判定することができる。また移動平均値からの乖離が所定値以下であるか否かにより判定してもよい。 When the ratio between the total voltage Vt ′ during the convergence period and the leakage detection voltage Vg is not substantially constant, the reliability determination unit 11d determines that an incorrect filter coefficient k is set in the IIR filter 11a, and the filter coefficient The leakage resistance values R1 and R2 based on the total voltage Vt ′ calculated by the IIR filter 11a in which k is set are determined to be invalid. Whether or not the ratio between the total voltage Vt ′ during the convergence period and the leakage detection voltage Vg is substantially constant can be determined, for example, based on whether or not the difference from the previous value is a predetermined value or less. . Moreover, you may determine by the deviation from a moving average value being below a predetermined value.
 信頼性判定部11dは、総電圧Vtを監視して総電圧Vtが実質的に一定であれば、上記フィルタ係数kの信頼性判定を実行せずに、漏電抵抗推定部11bにより算出された漏電抵抗値R1、R2を有効と判定する。即ち、総電圧Vtが実質的に一定であれば、総電圧Vt’と漏電検出用電圧Vgの比が一定であるか否かに関わらず、漏電抵抗推定部11bにより算出された漏電抵抗値R1、R2を有効と判定する。総電圧Vtが一定な期間は、漏電抵抗が大きく変動していないと推定できるため、過去に算出した漏電抵抗値R1、R2の信頼性が高いと推定できる。上記フィルタ係数kの信頼性判定を停止すれば、処理部11の演算量を削減することができ、処理部11の負荷を軽減することができる。 The reliability determination unit 11d monitors the total voltage Vt, and if the total voltage Vt is substantially constant, the reliability determination unit 11d does not perform the reliability determination of the filter coefficient k and calculates the leakage current calculated by the leakage resistance estimation unit 11b. The resistance values R1 and R2 are determined to be valid. That is, if the total voltage Vt is substantially constant, the leakage resistance value R1 calculated by the leakage resistance estimation unit 11b regardless of whether the ratio between the total voltage Vt ′ and the leakage detection voltage Vg is constant. , R2 is determined to be valid. Since it can be estimated that the leakage resistance has not fluctuated greatly during the period in which the total voltage Vt is constant, it can be estimated that the reliability of the leakage resistance values R1 and R2 calculated in the past is high. If the reliability determination of the filter coefficient k is stopped, the calculation amount of the processing unit 11 can be reduced, and the load on the processing unit 11 can be reduced.
 以上説明したように本実施の形態によれば、処理部11にIIRフィルタ11aを追加することにより、漏電検出用電圧Vgの時定数τgと総電圧Vtの時定数τtを実質的に一致させることができる。これにより総電圧Vtが急変しても、漏電検出用電圧Vgと総電圧Vtの比が崩れにくくなるため、ノイズの影響を受けにくくなり、ロバスト性が向上する。よって漏電抵抗値を高精度に推定することができる。 As described above, according to the present embodiment, by adding the IIR filter 11a to the processing unit 11, the time constant τg of the leakage detection voltage Vg and the time constant τt of the total voltage Vt are substantially matched. Can do. As a result, even if the total voltage Vt changes suddenly, the ratio between the leakage detection voltage Vg and the total voltage Vt is not easily lost, so that it is less susceptible to noise and the robustness is improved. Therefore, the leakage resistance value can be estimated with high accuracy.
 図12(a)、(b)は、漏電検出処理中の総電圧Vtと漏電検出用電圧Vgの波形推移の一例を示す図である。図12(a)は、本実施の形態に係る対策処理前の波形推移を示し、図12(b)は、本実施の形態に係る対策処理後の波形推移を示す。図12(a)に示す例では、処理部11が総電圧Vtと漏電検出用電圧Vgを取得する時点で、両波形の収束度が一致していない。一方、図12(b)に示す例では、処理部11が総電圧Vtと漏電検出用電圧Vgを取得する時点で、両波形の収束度が実質的に一致している。従って図12(b)に示す例の方が漏電抵抗値R1、R2の検出精度が高くなる。 FIGS. 12A and 12B are diagrams showing examples of waveform transitions of the total voltage Vt and the leakage detection voltage Vg during the leakage detection process. FIG. 12A shows the waveform transition before the countermeasure processing according to the present embodiment, and FIG. 12B shows the waveform transition after the countermeasure processing according to the present embodiment. In the example shown in FIG. 12A, the convergence of the two waveforms does not match when the processing unit 11 acquires the total voltage Vt and the leakage detection voltage Vg. On the other hand, in the example shown in FIG. 12B, when the processing unit 11 acquires the total voltage Vt and the leakage detection voltage Vg, the convergence degree of both waveforms substantially matches. Accordingly, the detection accuracy of the leakage resistance values R1 and R2 is higher in the example shown in FIG.
 以上、本発明を実施の形態をもとに説明した。実施の形態は例示であり、それらの各構成要素や各処理プロセスの組み合わせにいろいろな変形例が可能なこと、またそうした変形例も本発明の範囲にあることは当業者に理解されるところである。 The present invention has been described based on the embodiments. The embodiments are exemplifications, and it will be understood by those skilled in the art that various modifications can be made to combinations of the respective constituent elements and processing processes, and such modifications are within the scope of the present invention. .
 図8に示した実施例2に係る処理部11内の信頼性判定部11dは、図5に示した実施例1に係る処理部11内にも設けられてもよい。フィードフォワード方式であっても、電圧の測定誤差が大きい場合、フィルタ係数kの信頼性が低下する。信頼性判定部11dを設けることにより、漏電抵抗値R1、R2の信頼性をより向上させることができる。 The reliability determination unit 11d in the processing unit 11 according to the second embodiment illustrated in FIG. 8 may be provided in the processing unit 11 according to the first embodiment illustrated in FIG. Even in the feed-forward method, if the voltage measurement error is large, the reliability of the filter coefficient k decreases. By providing the reliability determination unit 11d, the reliability of the leakage resistance values R1 and R2 can be further improved.
 IIRフィルタ11aの代わりにアナログフィルタを用いてもよい。その場合、漏電検出用電圧Vgの時定数τgに応じて、抵抗や容量の定数を調整する。 An analog filter may be used instead of the IIR filter 11a. In this case, the resistance and capacitance constants are adjusted according to the time constant τg of the leakage detection voltage Vg.
 上述の実施の形態では、電源システム1の高圧ラインとシャーシアース2間の第1漏電抵抗5、及び電源システム1の低圧ラインとシャーシアース2間の第2漏電抵抗6を検出する例を説明した。この点、本実施の形態に係る漏電検出回路10は、複数のセル21-2nの任意のノードとシャーシアース2間の漏電も検出することができる。第1漏電検出用抵抗15/第2漏電検出用抵抗16を介してシャーシアース2に電流が流れる電流経路以外に、漏電電流経路が形成された場合、第1漏電検出用抵抗15/第2漏電検出用抵抗16に流れる電流量が変化する。従って、その変化が漏電検出用電圧Vgに現れてくる。 In the above-described embodiment, an example in which the first leakage resistance 5 between the high-voltage line of the power supply system 1 and the chassis ground 2 and the second leakage resistance 6 between the low-voltage line of the power supply system 1 and the chassis ground 2 has been described. . In this regard, the leakage detection circuit 10 according to the present embodiment can also detect a leakage between any node of the plurality of cells 21-2n and the chassis ground 2. When a leakage current path is formed in addition to the current path through which current flows through the chassis ground 2 via the first leakage detection resistor 15 / second leakage detection resistor 16, the first leakage detection resistor 15 / second leakage The amount of current flowing through the detection resistor 16 changes. Therefore, the change appears in the leakage detection voltage Vg.
 上述の実施の形態では、複数のセル21-2nの正極とシャーシアース2間に第1漏電検出用抵抗15を挿入し、複数のセル21-2nの負極とシャーシアース2間に第2漏電検出用抵抗16を挿入する例を説明した。この点、複数のセル21-2nの任意のノードとシャーシアース2間に漏電検出用抵抗を挿入してもよい。この場合も、当該漏電検出用抵抗の両端電圧を総電圧Vtで正規化する場合、両者の時定数を一致させることにより、検出精度が向上する。 In the above-described embodiment, the first leakage detection resistor 15 is inserted between the positive electrodes of the plurality of cells 21-2n and the chassis ground 2, and the second leakage detection is performed between the negative electrodes of the plurality of cells 21-2n and the chassis ground 2. The example of inserting the resistor 16 for use has been described. In this regard, a leakage detection resistor may be inserted between an arbitrary node of the plurality of cells 21-2n and the chassis ground 2. Also in this case, when the voltage across the leakage detection resistor is normalized with the total voltage Vt, the detection accuracy is improved by making both time constants coincide.
 なお、実施の形態は、以下の項目によって特定されてもよい。 Note that the embodiment may be specified by the following items.
[項目1]
 直列接続された複数のセル(21-2n)とシャーシアース(2)間に漏電検出用の抵抗(15/16)を介して漏電検出用の電流が流れると、前記漏電検出用の抵抗(15/16)の両端電圧を漏電検出用の電圧として検出する漏電検出用の電圧検出部(12)と、
 前記複数のセル(21-2n)の各セルの電圧を検出するためのセル電圧検出用の電圧検出部(50)から前記複数のセル(21-2n)の総電圧を取得し、前記漏電検出用の電圧検出部(12)から前記漏電検出用の電圧を取得し、取得した前記総電圧と前記漏電検出用の電圧をもとに、前記複数のセル(21-2n)と前記シャーシアース(2)間の漏電抵抗値を推定する処理部(11)と、を備え、
 前記複数のセル(21-2n)と前記シャーシアース(2)はコンデンサ(3/4)を介して接続されており、
 前記セル電圧検出用の電圧検出部(50)から前記処理部(11)に入力される前記総電圧の時定数は固定であり、前記漏電検出用の電圧検出部(12)から前記処理部(11)に入力される前記漏電検出用の電圧の時定数は漏電抵抗(5/6)に応じて可変であり、
 前記処理部(11)は、前記漏電検出用の電圧の時定数に前記総電圧の時定数を対応させるために前記総電圧にフィルタ(11a)を適用し、当該フィルタ(11a)を適用した後の前記総電圧と、前記漏電検出用の電圧をもとに前記漏電抵抗値を推定することを特徴とする漏電検出回路(10)。
 これによれば、漏電抵抗値を高精度に推定することができる。
[項目2]
 前記処理部(11)は、前記漏電検出用の電圧検出部(12)から入力される前記漏電検出用の電圧の入力波形の少なくとも3点の電圧を検出して、前記漏電検出用の電圧の時定数を推定し、推定した時定数をもとに前記フィルタ(11a)を調整することを特徴とする項目1に記載の漏電検出回路(10)。
 これによれば、フィードフォワード方式で、フィルタ(11a)を適応的に調整することができる。
[項目3]
 前記処理部(11)は、過去に推定した漏電抵抗値をもとに前記フィルタ(11a)を調整することを特徴とする項目1に記載の漏電検出回路(10)。
 これによれば、フィードバック方式で、フィルタ(11a)を適応的に調整することができる。
[項目4]
 前記処理部(11)は、前記漏電検出用の電圧の時定数をもとに推定される前記漏電検出用の電圧の波形収束点以降において、前記漏電検出用の電圧と前記総電圧との比が実質的に一定でない場合、前記漏電抵抗値を無効とすることを特徴とする項目2または3に記載の漏電検出回路(10)。
 これによれば、漏電抵抗値の推定精度をさらに高めることができる。
[項目5]
 前記処理部(11)は、前記総電圧が実質的に一定である場合、前記比が一定であるか否かに関わらず、前記漏電抵抗値を有効とすることを特徴とする項目4に記載の漏電検出回路(10)。
 これによれば、処理部(11)の負荷を軽減することができる。
[項目6]
 前記漏電検出用の電圧検出部(12)は、前記複数のセル(21-2n)の正極と前記シャーシアース(2)間に第1の漏電検出用の抵抗(15)を介して漏電検出用の電流が流れると、前記第1の漏電検出用の抵抗(15)の両端電圧を漏電検出用の電圧として検出し、前記複数のセル(21-2n)の負極と前記シャーシアース(2)間に第2の漏電検出用の抵抗(16)を介して漏電検出用の電流が流れると、前記第2の漏電検出用の抵抗(16)の両端電圧を漏電検出用の電圧として検出し、
 前記複数のセル(21-2n)の正極と前記シャーシアース(2)は第1のコンデンサ(3)を介して接続されており、前記複数のセル(21-2n)の負極と前記シャーシアース(2)は第2のコンデンサ(4)を介して接続されており、
 前記処理部(11)は、前記総電圧と前記漏電検出用の電圧をもとに、前記複数のセル(21-2n)の正極と前記シャーシアース(2)間の第1の漏電抵抗値、及び前記複数のセル(21-2n)の負極と前記シャーシアース(2)間の第2の漏電抵抗値を推定することを特徴とする項目1から5のいずれか1項に記載の漏電検出回路(10)。
 これによれば、複数のセル(21-2n)の正極とシャーシアース(2)間の第1の漏電抵抗値と、複数のセル(21-2n)の負極とシャーシアース(2)間の第2の漏電抵抗値を高精度に推定することができる。
[項目7]
 直列接続された複数のセル(21-2n)と、
 前記複数のセル(21-2n)とシャーシアース(2)間の漏電を検出する項目1から6のいずれか1項に記載の漏電検出回路(10)と、
 を備えることを特徴とする車両用電源システム(1)。
 これによれば、漏電抵抗値を高精度に推定することができる車両用電源システム(1)を構築することができる。
[Item 1]
When a current for leakage detection flows between the plurality of cells (21-2n) connected in series and the chassis ground (2) via the resistor (15/16) for detecting leakage, the leakage detection resistor (15 / 16) voltage detection unit (12) for detecting leakage, detecting the voltage at both ends as a voltage for detecting leakage,
A total voltage of the plurality of cells (21-2n) is acquired from a voltage detection unit (50) for cell voltage detection for detecting a voltage of each cell of the plurality of cells (21-2n), and the leakage detection is performed. The leakage detection voltage is acquired from the voltage detection unit (12), and based on the acquired total voltage and the leakage detection voltage, the plurality of cells (21-2n) and the chassis ground ( And 2) a processing unit (11) for estimating a leakage resistance value between
The plurality of cells (21-2n) and the chassis ground (2) are connected via a capacitor (3/4),
The time constant of the total voltage input from the voltage detection unit (50) for cell voltage detection to the processing unit (11) is fixed, and the voltage detection unit (12) for leakage detection detects the processing unit (12). The time constant of the leakage detection voltage input to 11) is variable according to the leakage resistance (5/6),
After applying the filter (11a) to the total voltage and applying the filter (11a), the processing unit (11) applies the time constant of the total voltage to the time constant of the leakage detection voltage. The leakage detection circuit (10), wherein the leakage resistance value is estimated based on the total voltage and the leakage detection voltage.
According to this, it is possible to estimate the leakage resistance value with high accuracy.
[Item 2]
The processing unit (11) detects at least three voltages in the input waveform of the leakage detection voltage input from the leakage detection voltage detection unit (12), and detects the leakage detection voltage. The leakage detection circuit (10) according to item 1, wherein a time constant is estimated and the filter (11a) is adjusted based on the estimated time constant.
According to this, the filter (11a) can be adaptively adjusted by the feed forward method.
[Item 3]
The leakage detection circuit (10) according to item 1, wherein the processing unit (11) adjusts the filter (11a) based on a leakage resistance value estimated in the past.
According to this, the filter (11a) can be adaptively adjusted by a feedback method.
[Item 4]
The processing unit (11) includes a ratio between the leakage detection voltage and the total voltage after a waveform convergence point of the leakage detection voltage estimated based on a time constant of the leakage detection voltage. The leakage detection circuit (10) according to item 2 or 3, wherein the leakage resistance value is invalidated when the value is not substantially constant.
According to this, the estimation accuracy of the leakage resistance value can be further increased.
[Item 5]
Item 5. The item 4, wherein, when the total voltage is substantially constant, the processing unit (11) makes the leakage resistance value valid regardless of whether the ratio is constant or not. Earth leakage detection circuit (10).
According to this, the load on the processing unit (11) can be reduced.
[Item 6]
The leakage detection voltage detection unit (12) is configured to detect leakage through a first leakage detection resistor (15) between the positive electrodes of the plurality of cells (21-2n) and the chassis ground (2). Current flows, the voltage between both ends of the first leakage detection resistor (15) is detected as a leakage detection voltage, and between the negative electrodes of the plurality of cells (21-2n) and the chassis ground (2). When a leakage detection current flows through the second leakage detection resistor (16), the voltage across the second leakage detection resistor (16) is detected as a leakage detection voltage,
The positive electrodes of the plurality of cells (21-2n) and the chassis ground (2) are connected via a first capacitor (3), and the negative electrodes of the plurality of cells (21-2n) and the chassis ground ( 2) is connected via a second capacitor (4),
The processing unit (11), based on the total voltage and the leakage detection voltage, a first leakage resistance value between the positive electrodes of the plurality of cells (21-2n) and the chassis ground (2), 6. The leakage detection circuit according to claim 1, wherein a second leakage resistance value between the negative electrodes of the plurality of cells (21-2 n) and the chassis ground (2) is estimated. (10).
According to this, the first leakage resistance value between the positive electrodes of the plurality of cells (21-2n) and the chassis ground (2), and the first leakage resistance value between the negative electrodes of the plurality of cells (21-2n) and the chassis ground (2). The leakage resistance value of 2 can be estimated with high accuracy.
[Item 7]
A plurality of cells (21-2n) connected in series;
The leakage detection circuit (10) according to any one of items 1 to 6, which detects leakage between the plurality of cells (21-2n) and the chassis ground (2),
A vehicle power supply system (1) comprising:
According to this, the vehicle power supply system (1) that can estimate the leakage resistance value with high accuracy can be constructed.
 1 電源システム、 2 シャーシアース、 3 第1コンデンサ、 4 第2コンデンサ、 5 第1漏電抵抗、 6 第2漏電抵抗、 21-2n セル、 31-3n 抵抗、 41-4m コンデンサ、 50 電圧検出部、 50a マルチプレクサ、 50b A/D変換器、 50c セル電圧加算部、 50d IIRフィルタ、 10 漏電検出回路、 11 処理部、 11a IIRフィルタ、 11b 漏電抵抗推定部、 11c 時定数予測部、 11d 信頼性判定部、 12 差動アンプ、 13 A/D変換器、 14 第1電流制限抵抗、 15 第1漏電検出用抵抗、 16 第2漏電検出用抵抗、 17 第2電流制限抵抗、 18 第1スイッチ、 19 第2スイッチ、 61,62 遮断スイッチ、 71 正極端子、 72 負極端子。 1 power system, 2 chassis ground, 3 first capacitor, 4 second capacitor, 5 first leakage resistance, 6 second leakage resistance, 21-2n cell, 31-3n resistance, 41-4m capacitor, 50 voltage detector, 50a multiplexer, 50b A / D converter, 50c cell voltage addition unit, 50d IIR filter, 10 leakage detection circuit, 11 processing unit, 11a IIR filter, 11b leakage resistance estimation unit, 11c time constant prediction unit, 11d reliability determination unit , 12 differential amplifier, 13 A / D converter, 14 first current limiting resistor, 15 first leakage detection resistor, 16 second leakage detection resistor, 17 second current limiting resistor, 18 first switch, 19th switch 2 switches, 61, 62 shut off Pitch, 71 positive electrode terminal, 72 the negative terminal.

Claims (7)

  1.  直列接続された複数のセルとシャーシアース間に漏電検出用の抵抗を介して漏電検出用の電流が流れると、前記漏電検出用の抵抗の両端電圧を漏電検出用の電圧として検出する漏電検出用の電圧検出部と、
     前記複数のセルの各セルの電圧を検出するためのセル電圧検出用の電圧検出部から前記複数のセルの総電圧を取得し、前記漏電検出用の電圧検出部から前記漏電検出用の電圧を取得し、取得した前記総電圧と前記漏電検出用の電圧をもとに、前記複数のセルと前記シャーシアース間の漏電抵抗値を推定する処理部と、を備え、
     前記複数のセルと前記シャーシアースはコンデンサを介して接続されており、
     前記セル電圧検出用の電圧検出部から前記処理部に入力される前記総電圧の時定数は固定であり、前記漏電検出用の電圧検出部から前記処理部に入力される前記漏電検出用の電圧の時定数は漏電抵抗に応じて可変であり、
     前記処理部は、前記漏電検出用の電圧の時定数に前記総電圧の時定数を対応させるために前記総電圧にフィルタを適用し、当該フィルタを適用した後の前記総電圧と、前記漏電検出用の電圧をもとに前記漏電抵抗値を推定することを特徴とする漏電検出回路。
    When a leakage detection current flows between a plurality of cells connected in series and chassis ground via a leakage detection resistor, the voltage across the leakage detection resistor is detected as a leakage detection voltage. A voltage detector of
    The total voltage of the plurality of cells is obtained from a voltage detection unit for cell voltage detection for detecting the voltage of each cell of the plurality of cells, and the voltage for leakage detection is obtained from the voltage detection unit for leakage detection. A processing unit that acquires and estimates a leakage resistance value between the plurality of cells and the chassis ground, based on the acquired total voltage and the leakage detection voltage.
    The plurality of cells and the chassis ground are connected via a capacitor,
    The time constant of the total voltage input from the voltage detection unit for cell voltage detection to the processing unit is fixed, and the leakage detection voltage input from the voltage detection unit for leakage detection to the processing unit The time constant of is variable according to the leakage resistance,
    The processing unit applies a filter to the total voltage in order to make the time constant of the total voltage correspond to the time constant of the leakage detection voltage, the total voltage after applying the filter, and the leakage detection A leakage detection circuit, wherein the leakage resistance value is estimated based on a voltage for use.
  2.  前記処理部は、前記漏電検出用の電圧検出部から入力される前記漏電検出用の電圧の入力波形の少なくとも3点の電圧を検出して、前記漏電検出用の電圧の時定数を推定し、推定した時定数をもとに前記フィルタを調整することを特徴とする請求項1に記載の漏電検出回路。 The processing unit detects at least three voltages of the input waveform of the leakage detection voltage input from the leakage detection voltage detection unit, and estimates a time constant of the leakage detection voltage; The leakage detecting circuit according to claim 1, wherein the filter is adjusted based on the estimated time constant.
  3.  前記処理部は、過去に推定した漏電抵抗値をもとに前記フィルタを調整することを特徴とする請求項1に記載の漏電検出回路。 The leakage detecting circuit according to claim 1, wherein the processing unit adjusts the filter based on a leakage resistance value estimated in the past.
  4.  前記処理部は、前記漏電検出用の電圧の時定数をもとに推定される前記漏電検出用の電圧の波形収束点以降において、前記漏電検出用の電圧と前記総電圧との比が実質的に一定でない場合、前記漏電抵抗値を無効とすることを特徴とする請求項2または3に記載の漏電検出回路。 The processing unit has a substantial ratio of the leakage detection voltage and the total voltage after the waveform convergence point of the leakage detection voltage estimated based on a time constant of the leakage detection voltage. 4. The leakage detecting circuit according to claim 2, wherein the leakage resistance value is invalidated if not constant.
  5.  前記処理部は、前記総電圧が実質的に一定である場合、前記比が一定であるか否かに関わらず、前記漏電抵抗値を有効とすることを特徴とする請求項4に記載の漏電検出回路。 The leakage current according to claim 4, wherein when the total voltage is substantially constant, the processing unit validates the leakage resistance value regardless of whether the ratio is constant or not. Detection circuit.
  6.  前記漏電検出用の電圧検出部は、前記複数のセルの正極と前記シャーシアース間に第1の漏電検出用の抵抗を介して漏電検出用の電流が流れると、前記第1の漏電検出用の抵抗の両端電圧を漏電検出用の電圧として検出し、前記複数のセルの負極と前記シャーシアース間に第2の漏電検出用の抵抗を介して漏電検出用の電流が流れると、前記第2の漏電検出用の抵抗の両端電圧を漏電検出用の電圧として検出し、
     前記複数のセルの正極と前記シャーシアースは第1のコンデンサを介して接続されており、前記複数のセルの負極と前記シャーシアースは第2のコンデンサを介して接続されており、
     前記処理部は、前記総電圧と前記漏電検出用の電圧をもとに、前記複数のセルの正極と前記シャーシアース間の第1の漏電抵抗値、及び前記複数のセルの負極と前記シャーシアース間の第2の漏電抵抗値を推定することを特徴とする請求項1から5のいずれか1項に記載の漏電検出回路。
    When a current for leakage detection flows through the first leakage detection resistor between the positive electrodes of the plurality of cells and the chassis ground, the voltage detection unit for leakage detection detects the first leakage detection The voltage across the resistor is detected as a leakage detection voltage, and when a leakage detection current flows between the negative electrodes of the plurality of cells and the chassis ground via a second leakage detection resistor, the second The voltage across the resistor for detecting leakage is detected as the voltage for detecting leakage,
    The positive electrodes of the plurality of cells and the chassis ground are connected via a first capacitor, the negative electrodes of the plurality of cells and the chassis ground are connected via a second capacitor,
    The processing unit includes a first leakage resistance value between the positive electrode of the plurality of cells and the chassis ground, and a negative electrode of the plurality of cells and the chassis ground based on the total voltage and the voltage for detecting leakage. The leakage detection circuit according to claim 1, wherein a second leakage resistance value is estimated.
  7.  直列接続された複数のセルと、
     前記複数のセルとシャーシアース間の漏電を検出する請求項1から6のいずれか1項に記載の漏電検出回路と、
     を備えることを特徴とする車両用電源システム。
    A plurality of cells connected in series;
    The leakage detection circuit according to any one of claims 1 to 6, which detects a leakage between the plurality of cells and the chassis ground.
    A vehicle power supply system comprising:
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