JP2004245600A - Insulation resistance detection device - Google Patents

Insulation resistance detection device Download PDF

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Publication number
JP2004245600A
JP2004245600A JP2003032690A JP2003032690A JP2004245600A JP 2004245600 A JP2004245600 A JP 2004245600A JP 2003032690 A JP2003032690 A JP 2003032690A JP 2003032690 A JP2003032690 A JP 2003032690A JP 2004245600 A JP2004245600 A JP 2004245600A
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insulation resistance
voltage
connection point
detection
detection device
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Tsutomu Saigo
勉 西郷
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Yazaki Corp
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Yazaki Corp
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    • Y—GENERAL 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/72—Electric energy management in electromobility

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  • Measurement Of Resistance Or Impedance (AREA)
  • Electric Propulsion And Braking For Vehicles (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insulation resistance detection device capable of securely preventing false-operation and trouble. <P>SOLUTION: In this insulation resistance detection device 30, pulse signals are applied, through a detection resistance 2 and the series circuit of a coupling capacitor 3, to a DC power system 60 electrically insulated from a conductive member 10 by an insulation resistance R, and a voltage as an insulation resistance value detection signal representing the resistance value of the insulation resistance R appearing at a connection point p between the detection resistance 2 and the coupling capacitor 3 is amplified by an amplifying means 4 and outputted. Also, an inhibiting means 31 inhibiting the input of the negative potential component of the voltage into the amplifying means 4 is installed between the connection point p and the amplifying means 4. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、絶縁抵抗検出装置に関し、より詳細には、導電性部材に対して絶縁抵抗により電気的に絶縁される直流電源系統に対して、検出用抵抗及びカップリングコンデンサの直列回路を介してパルス信号を印加し、前記検出用抵抗と前記カップリングコンデンサとの接続点に現れる、前記絶縁抵抗の抵抗値を表す絶縁抵抗値検出信号としての電圧を、増幅手段により増幅して出力する絶縁抵抗検出装置に関するものである。
【０００２】
【従来の技術】
従来より駆動源として高電圧のバッテリを備えている自動車、電気自動車等の場合、そのバッテリによる感電を防止するために、車両ボディ（導電性部材）とバッテリとが電気的に絶縁された構造となっている。ところが、例えばバッテリの材質変質、付着物等が原因で、その絶縁特性が劣化して車両ボディとバッテリとが電気的に接続されてしまうという問題が生じる。これを回避するものとして絶縁抵抗検出装置がある。
【０００３】
例えば、図５は従来の電気自動車の地絡検知システムの回路図を示し、この地絡検知システムＡは、リレー１１と抵抗１２とからなり車体１０と母線６１との間に接続される地絡試行回路１と、バッファ４０が出力する矩形波４１１を母線６１に印加する、検出用抵抗２及びカップリングコンデンサ３と、接続点ｐの信号（矩形波）４１２を反転入力端子４１に入力し、基準電圧Ｖｒを非反転入力端子４２に入力する比較器４と、発振部５０を有する制御器５と、トランジスタ５１と、ＬＥＤ制御器５２と、ＬＥＤ５３とを備え、車載バッテリ６と、走行用の交流モータ７と、入力側を母線６１、６２に電気接続し、出力側を交流給電線８１、８２、８３を介して交流モータ７に電気接続したＤＣ・ＡＣインバータ８とを有する電気自動車に組み付けられる。（特許文献１参照）
【０００４】
この地絡検知システムＡにおいて、矩形波５０１をカップリングコンデンサ３を介して高電圧系に印可すると、抵抗（絶縁抵抗）Ｒに応じて矩形波５０１の波高値が変化するため、その波高値をアンプ４で増幅して出力し、制御器５はその出力に基づいて絶縁抵抗低下を判定する。例えば地絡（抵抗Ｒ）が発生すると、接続点ｐの電圧が変化し、比較器４の出力がパルス出力からＨｉ出力に切り替わり、制御器５がパルス出力をトランジスタ５１に送出し、ＬＥＤ制御器５２がＬＥＤ５３を点灯させる。
【０００５】
【特許文献１】
特開平１０−２２１３９５号公報 （第３−５頁、第１図）
【０００６】
【発明が解決しようとする課題】
しかしながら、上述したシステムは単電源で構成されているため、アンプ４にノイズ等による電圧の負電圧成分が入力されてしまうと、アンプ４が誤動作または故障する可能性があった。すると、絶縁抵抗Ｒの絶縁特性の劣化を速やかに検出することができず、車両ボディとバッテリとの電気的接続を回避することができない可能性があった。
【０００７】
よって本発明は、上述した問題点に鑑み、誤動作、故障を確実に防止することができる絶縁抵抗検出装置を提供することを課題としている。
【０００８】
【課題を解決するための手段】
上記課題を解決するため本発明によりなされた請求項１記載の絶縁抵抗検出装置は、導電性部材に対して絶縁抵抗により電気的に絶縁される直流電源系統に対して、検出用抵抗及びカップリングコンデンサの直列回路を介してパルス信号を印加し、前記検出用抵抗と前記カップリングコンデンサとの接続点に現れる、前記絶縁抵抗の抵抗値を表す絶縁抵抗値検出信号としての電圧を、増幅手段により増幅して出力する絶縁抵抗検出装置において、前記接続点と前記増幅手段との間に、前記電圧の負電位成分が前記増幅手段に入力されることを阻止することを特徴とする。
【０００９】
上記請求項１に記載した本発明の絶縁抵抗検出装置によれば、接続点に現れる絶縁抵抗の抵抗値を表す絶縁抵抗値検出信号としての電圧が負電圧成分になると、阻止手段はその負電圧成分が増幅手段に入力されることを阻止する。よって、直流電源系統においてスイッチングノイズ等が発生して接続点に現れる電位が負電圧成分となっても、阻止手段によってその負電位成分が増幅手段に入力されることが阻止されることから、負電位成分が入力されて増幅手段が誤動作や故障する等の不具合が発生する可能性を排除することができる。従って、絶縁抵抗検出装置の誤動作、故障を確実に防止することができるため、絶縁抵抗検出装置の出力に基づいて絶縁抵抗の劣化を確実に検出することができる。
【００１０】
上記課題を解決するためになされた請求項２記載の発明は、請求項１に記載の絶縁抵抗検出装置において、前記接続点と前記阻止手段との間に、前記直流電源系統にて発生した異常信号に応じた前記電圧の異常電圧成分を取り除くフィルタをさらに設けることを特徴とする。
【００１１】
上記請求項２に記載した本発明の絶縁抵抗検出装置によれば、直流電源系統にて発生した異常信号に応じた電圧の異常電圧成分は、フィルタによって取り除かれて阻止手段に伝達される。よって、直流電源系統に発生した異常信号に応じた電圧の異常電圧成分はフィルタによって取り除かれるが、このフィルタが取り除けなかった異常電圧成分が負電位成分であると、阻止手段はその負電位成分が増幅手段に入力されることを阻止することから、フィルタが阻止手段と増幅手段の前段に設けられても、増幅手段の誤動作や故障を確実に排除することができる。
【００１２】
【発明の実施の形態】
以下、本発明に係る絶縁抵抗検出装置の一実施の形態を、図１〜図４の図面を参照して説明する。なお、従来の技術のところで説明したものと同一あるいは相当する部分には同一符号を付してその詳細な説明は省略する。
【００１３】
ここで、図１は本発明の絶縁抵抗検出装置の基本構成の一例を示す構成図であり、図２は図１中のフィルタの一例を示す回路図であり、図３は絶縁抵抗検出装置における電圧波形を示すグラフであり、図４は絶縁抵抗検出装置の他の実施の形態を示す構成図である。
【００１４】
図１において、車体ボディ（導電性部材）１０に対して絶縁抵抗Ｒにより電気的に絶縁される高電圧系の直流電源系統６０に対して、検出用抵抗２及びカップリングコンデンサ３の直列回路を介してパルス信号を印加し、前記検出用抵抗２と前記カップリングコンデンサ３との接続点ｐに現れる、前記絶縁抵抗Ｒの抵抗値を表す絶縁抵抗値検出信号としての電圧を、アンプ（増幅手段）４により増幅して出力する絶縁抵抗検出装置３０は、前記接続点ｐと前記アンプ４との間に、前記電圧の負電位成分が前記アンプ４に入力されることを阻止するダイオード（阻止手段）３１を備える。
【００１５】
なお、直流電源系統６０は、従来の技術で説明したように、車載バッテリ６と、走行用の交流モータ７と、入力側を母線６１、６２に電気的に接続し、出力側を交流給電線８１、８２、８３を介して交流モータ７に電気接続したＤＣ−ＡＣ変換器としてのインバータ８とを有する。また、直流電源系統６０は、２つの絶縁抵抗Ｒとコンデンサ６３、６４と、漏電抵抗６５とを介して車体ボディ１０に対して絶縁されている。
【００１６】
絶縁抵抗検出装置３０はさらに、発振器等の発振部５０を備え、この発振部５０は、一方が検出用抵抗２が接続され、他方は接地されている。そして、振れ幅ＶＯＳ（０＜ＶＯＳ＜ＶＣＣ）のパルス信号を発振する。また、検出用抵抗２の他方は接続点ｐを介してカップリングコンデンサ３の一方に接続され、カップリングコンデンサ３の他方は直流電源系統６０のコンデンサ６４、車載バッテリ６、母線６２及び絶縁抵抗Ｒに接続されている。
【００１７】
電源ＶＣＣからの電力供給されるアンプ４の入力には、アノードが接地されたダイオード３１のカソードとフィルタ３２の一方が接続されている。そして、このダイオード３１によって電圧の負電圧成分を排除し、正電圧成分の一定レベルのみがアンプ４に入力されるようにダイオード３１を設けている（クランプ回路）。また、フィルタ３２の他方は、検出用抵抗２とカップリングコンデンサ３との接続点ｐに接続されている。
【００１８】
フィルタ３２の一例としては、図２に示すように、バンドパスフィルタを用い、接続点Ｐからローパスフィルタとハイパスフィルタを順次接続して構成している。そして、このフィルタ３２は、直流電流系統６０にて発生したインバータ８のスイッチングノイズ等を取り除いている。
【００１９】
次に、本発明の絶縁抵抗検出装置３０の動作（作用）の一例を説明する。
発振部５０により振れ幅ＶＯＳのパルス信号が発振されると、カップリングコンデンサ３を通して直流電源系統６０にパルス波が印加される。そして、絶縁抵抗Ｒに応じてパルス波の波高値が変化するため、この波高値はアンプ４によって増幅されて出力される。よって、その出力レベルに基づいて絶縁抵抗Ｒの抵抗値を検出することができる。
【００２０】
詳細には、接続点ｐに現れる絶縁抵抗の抵抗値を表す絶縁抵抗値検出信号としての電圧は、フィルタ３２とダイオード３１によって定められる一定レベルの正電圧成分がアンプ４に入力される。そして、直流電源系統６０においてスイッチングノイズ等が発生して接続点ｐに現れる電位が負電圧成分になると、ダイオード４はその負電圧成分がアンプ４に入力されることを阻止する。
【００２１】
図３において、図３（ａ）のパルス信号はフィルタ３２のローパスフィルタを通過すると、図３（ｂ）に示すパルス信号となる。そして、図１中のダイオード３１を設けていない場合（阻止手段なし）は、ハイパスフィルタの出力は通常正負に振れることから、図３（ｃ）に示すように、パルス信号は正負に振幅する波形となり、負電圧成分がアンプ４に入力されることになる。
【００２２】
しかしながら、本発明のように阻止手段であるダイオード３１をアンプ４の前段に設けることで、図３（ｄ）に示すように、図３（ｃ）のパルス信号から負電位成分が排除されたパルス信号としてアンプ４に入力される。よって、ハイパスフィルタの出力が負になると、ダイオード３１は負電位成分がアンプ４に入力されることを阻止することになる。
【００２３】
よって、直流電源系統６０においてスイッチングノイズ等が発生して接続点ｐに現れる電位が負電圧成分となっても、ダイオード（阻止手段）３１によってその負電位成分がアンプ（増幅手段）４に入力されることが阻止されることから、負電位成分が入力されてアンプ４が誤動作や故障する等の不具合が発生する可能性を排除することができる。
【００２４】
従って、絶縁抵抗検出装置３０の誤動作、故障を確実に防止することができるため、絶縁抵抗検出装置３０の出力に基づいて絶縁抵抗Ｒの劣化を確実に検出することができる。その結果、絶縁抵抗Ｒの絶縁特性の劣化を速やかに検出することができるため、車体ボディ（導電性部材）１０と車載バッテリ６との電気的接続を確実に回避することができる。
【００２５】
また、直流電源系統６０に発生した異常信号に応じた電圧の異常電圧成分はフィルタ３２によって取り除かれるが、このフィルタ３２が取り除けなかった異常電圧成分が負電位成分であると、ダイオード３１はその負電位成分がアンプ４に入力されることを阻止することから、フィルタ３２がダイオード３１とアンプ４の前段に設けられても、アンプ４の誤動作や故障を確実に排除することができる。
【００２６】
また、上述した本実施の形態では、請求項中の阻止手段としてダイオード３１を用いた場合について説明したが、本発明はこれに限定するものではなく、種々異なる実施形態とすることもできる。以下に、他の実施の形態の一例を図４の図面を参照して説明する。なお、上述した実施の形態のところで説明したものと同一あるいは相当する部分には同一符号を付してその詳細な説明は省略する。
【００２７】
図４に示す絶縁抵抗検出装置３０と直流電源系統６０との基本構成は、図１の基本構成とほぼ同一であり、その差異は、上述した絶縁抵抗検出装置３０の構成（図１参照）から発振部５０を削除し、絶縁抵抗検出装置３０の入力に外部のマイクロ・コンピュータ（以下、マイコンともいう）７０からの前記パルス信号を入力するようにしている。
【００２８】
また、他の実施の形態における絶縁抵抗検出装置３０の阻止手段としては、スイッチ３１ａを用いており、このスイッチ３１ａのオン／オフはマイコン７０によって制御されるように構成している。例えば、マイコン７０は出力するパルス波形がＬｏレベルのときにスイッチ３１ａをオン状態とし、Ｈｉレベルのときにオフ状態となうように、スイッチ３１ａを制御する。
【００２９】
このような構成としても、直流電源系統６０においてスイッチングノイズ等が発生して接続点ｐに現れる電位が負電圧成分となっても、スイッチ（阻止手段）３１ａによってその負電位成分がアンプ４に入力されることが阻止されることから、負電位成分が入力されてアンプ４が誤動作や故障する等の不具合が発生する可能性を排除することができる。よって、上述した実施の形態と同様の効果を得ることができる。
【００３０】
さらに、ダイオード３１はその順方向電圧が０．３Ｖ以下のものは殆どないため、このような場合に阻止手段としてスイッチ３１ａを用いれば、０．３Ｖ以下の場合でも対応することができる。
【００３１】
また、上述した実施の形態では、請求項中の阻止手段にダイオード３１及びスイッチ３１ａを用いた場合について説明したが、本発明はこれに限定するものではなく、阻止手段として他にも半波整流回路、フォトモスリレー、フォトカプラ、ＣＭＯＳアナログスイッチなどを用いることができる。
【００３２】
【発明の効果】
以上説明したように請求項１に記載した本発明の絶縁抵抗検出装置によれば、直流電源系統においてスイッチングノイズ等が発生して接続点に現れる電位が負電圧成分となっても、阻止手段によってその負電位成分が増幅手段に入力されることが阻止されることから、負電位成分が入力されて増幅手段が誤動作や故障する等の不具合が発生する可能性を排除することができる。従って、絶縁抵抗検出装置の誤動作、故障を確実に防止することができるため、絶縁抵抗検出装置の出力に基づいて絶縁抵抗の劣化を確実に検出することができる。
【００３３】
請求項２に記載の発明によれば、請求項１に記載の発明の効果に加え、直流電源系統に発生した異常信号に応じた電圧の異常電圧成分はフィルタによって取り除かれるが、このフィルタが取り除けなかった異常電圧成分が負電位成分であると、阻止手段はその負電位成分が増幅手段に入力されることを阻止することから、フィルタが阻止手段と増幅手段の前段に設けられても、増幅手段の誤動作や故障を確実に排除することができる。
【図面の簡単な説明】
【図１】本発明の絶縁抵抗検出装置の基本構成の一例を示す構成図である。
【図２】図１中のフィルタの一例を示す回路図である。
【図３】絶縁抵抗検出装置における電圧波形を示すグラフである。
【図４】絶縁抵抗検出装置の他の実施の形態を示す構成図である。
【図５】従来の電気自動車の地絡検知システムの回路図である。
【符号の説明】
２ 検出用抵抗
３ カップリングコンデンサ
４ アンプ（増幅手段）
１０ 車体ボディ（導電性部材）
３１ ダイオード（阻止手段）
３１ａ スイッチ（阻止手段）
３２ フィルタ
６０ 直流電源系統
Ｒ 絶縁抵抗[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an insulation resistance detection device, and more particularly, to a DC power supply system that is electrically insulated by an insulation resistance with respect to a conductive member, through a series circuit of a detection resistance and a coupling capacitor. An insulation resistor that applies a pulse signal, amplifies a voltage as an insulation resistance detection signal, which appears at a connection point between the detection resistor and the coupling capacitor and indicates a resistance value of the insulation resistor, by an amplification unit and outputs the amplified voltage. The present invention relates to a detection device.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in the case of an automobile, an electric automobile, or the like having a high-voltage battery as a drive source, a structure in which a vehicle body (conductive member) and the battery are electrically insulated to prevent electric shock due to the battery. Has become. However, there arises a problem that, for example, due to the deterioration of the material of the battery, the attached matter, or the like, the insulating property thereof is deteriorated, and the vehicle body and the battery are electrically connected. In order to avoid this, there is an insulation resistance detecting device.
[0003]
For example, FIG. 5 shows a circuit diagram of a conventional ground fault detection system for an electric vehicle. This ground fault detection system A is composed of a relay 11 and a resistor 12, and is connected between the vehicle body 10 and the bus 61. The trial circuit 1, the detection resistor 2 and the coupling capacitor 3 for applying the rectangular wave 411 output from the buffer 40 to the bus 61, and the signal (rectangular wave) 412 at the connection point p are input to the inverting input terminal 41. A comparator 4 having a reference voltage Vr input to a non-inverting input terminal 42, a controller 5 having an oscillator 50, a transistor 51, an LED controller 52, and an LED 53 are provided. An electric vehicle having an AC motor 7 and a DC / AC inverter 8 whose input side is electrically connected to the buses 61 and 62 and whose output side is electrically connected to the AC motor 7 via AC power supply lines 81, 82 and 83. Attached seen. (See Patent Document 1)
[0004]
In the ground fault detection system A, when the rectangular wave 501 is applied to the high voltage system via the coupling capacitor 3, the peak value of the rectangular wave 501 changes according to the resistance (insulation resistance) R, and the peak value is changed. The output is amplified by the amplifier 4, and the controller 5 determines a decrease in insulation resistance based on the output. For example, when a ground fault (resistance R) occurs, the voltage at the connection point p changes, the output of the comparator 4 switches from the pulse output to the Hi output, the controller 5 sends the pulse output to the transistor 51, and the LED controller 52 turns on the LED 53.
[0005]
[Patent Document 1]
JP-A-10-221395 (Page 3-5, FIG. 1)
[0006]
[Problems to be solved by the invention]
However, since the above-described system is configured by a single power supply, if a negative voltage component of a voltage due to noise or the like is input to the amplifier 4, the amplifier 4 may malfunction or break down. Then, the deterioration of the insulation characteristics of the insulation resistance R cannot be detected promptly, and it may not be possible to avoid the electrical connection between the vehicle body and the battery.
[0007]
Therefore, an object of the present invention is to provide an insulation resistance detecting device capable of reliably preventing malfunction and failure in view of the above-described problems.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the insulation resistance detecting device according to claim 1 is provided with a detection resistor and a coupling for a DC power supply system that is electrically insulated from a conductive member by an insulation resistance. A pulse signal is applied through a series circuit of a capacitor, and a voltage as an insulation resistance detection signal representing a resistance value of the insulation resistance, which appears at a connection point between the detection resistor and the coupling capacitor, is amplified by amplifying means. In the insulation resistance detecting device for amplifying and outputting, the negative potential component of the voltage is prevented from being input to the amplifying means between the connection point and the amplifying means.
[0009]
According to the insulation resistance detecting device of the present invention, when the voltage as the insulation resistance detection signal representing the resistance value of the insulation resistance appearing at the connection point becomes a negative voltage component, the blocking means operates the negative voltage. Blocks components from being input to the amplification means. Therefore, even if the switching noise or the like occurs in the DC power supply system and the potential appearing at the connection point becomes a negative voltage component, the blocking means prevents the negative potential component from being input to the amplifying means. It is possible to eliminate the possibility that a malfunction such as malfunction or failure of the amplifying means due to the input of the potential component occurs. Therefore, the malfunction and failure of the insulation resistance detection device can be reliably prevented, so that the deterioration of the insulation resistance can be reliably detected based on the output of the insulation resistance detection device.
[0010]
According to a second aspect of the present invention, there is provided an insulation resistance detecting apparatus as set forth in the first aspect, wherein an abnormality generated in the DC power supply system between the connection point and the blocking means. A filter for removing an abnormal voltage component of the voltage according to a signal is further provided.
[0011]
According to the insulation resistance detecting device of the present invention, the abnormal voltage component of the voltage corresponding to the abnormal signal generated in the DC power supply system is removed by the filter and transmitted to the blocking means. Therefore, the abnormal voltage component of the voltage corresponding to the abnormal signal generated in the DC power supply system is removed by the filter. If the abnormal voltage component that cannot be removed by the filter is a negative potential component, the blocking means causes the negative potential component to be removed. Since the input to the amplifying means is prevented, the malfunction and failure of the amplifying means can be reliably eliminated even if the filter is provided before the blocking means and the amplifying means.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of an insulation resistance detecting device according to the present invention will be described with reference to FIGS. The same or corresponding parts as those described in the description of the related art are denoted by the same reference numerals, and detailed description thereof will be omitted.
[0013]
Here, FIG. 1 is a configuration diagram showing an example of a basic configuration of an insulation resistance detection device of the present invention, FIG. 2 is a circuit diagram showing an example of a filter in FIG. 1, and FIG. FIG. 4 is a graph showing a voltage waveform, and FIG. 4 is a configuration diagram showing another embodiment of the insulation resistance detecting device.
[0014]
In FIG. 1, a series circuit of a detection resistor 2 and a coupling capacitor 3 is provided for a high-voltage DC power supply system 60 electrically insulated from a vehicle body (conductive member) 10 by an insulation resistor R. A pulse signal is applied through an amplifier (amplifying means), which appears at a connection point p between the detection resistor 2 and the coupling capacitor 3 and indicates a resistance value of the insulation resistor R as an insulation resistance detection signal. 4) The insulation resistance detecting device 30 which amplifies and outputs the signal by a diode (blocking means) between the connection point p and the amplifier 4 for preventing the negative potential component of the voltage from being input to the amplifier 4. ) 31 is provided.
[0015]
As described in the related art, the DC power supply system 60 is configured such that the vehicle-mounted battery 6, the AC motor 7 for traveling, the input side is electrically connected to the buses 61 and 62, and the output side is the AC power supply line. An inverter 8 as a DC-AC converter electrically connected to the AC motor 7 via 81, 82, 83. The DC power supply system 60 is insulated from the vehicle body 10 via two insulation resistances R, capacitors 63 and 64, and a leakage resistance 65.
[0016]
The insulation resistance detecting device 30 further includes an oscillating unit 50 such as an oscillator, and one of the oscillating units 50 is connected to the detecting resistor 2 and the other is grounded. Then, a pulse signal having a swing width V OS (0 <V OS <V CC ) is oscillated. The other of the detection resistors 2 is connected to one of the coupling capacitors 3 via a connection point p, and the other of the coupling capacitors 3 is connected to the capacitor 64 of the DC power supply system 60, the vehicle-mounted battery 6, the bus 62, and the insulation resistance R. It is connected to the.
[0017]
The amplifier input of 4 to be power supply from the power source V CC, while the cathode and the filter 32 of the diode 31 whose anode is grounded is connected. The diode 31 eliminates the negative voltage component of the voltage, and the diode 31 is provided so that only a certain level of the positive voltage component is input to the amplifier 4 (clamp circuit). The other end of the filter 32 is connected to a connection point p between the detection resistor 2 and the coupling capacitor 3.
[0018]
As an example of the filter 32, as shown in FIG. 2, a band-pass filter is used, and a low-pass filter and a high-pass filter are sequentially connected from a connection point P. The filter 32 removes switching noise and the like of the inverter 8 generated in the DC current system 60.
[0019]
Next, an example of the operation (action) of the insulation resistance detecting device 30 of the present invention will be described.
When the pulse signal of amplitude V OS by the oscillation unit 50 is oscillated, the pulse wave is applied to the DC power supply system 60 through a coupling capacitor 3. Since the peak value of the pulse wave changes according to the insulation resistance R, the peak value is amplified by the amplifier 4 and output. Therefore, the resistance value of the insulation resistor R can be detected based on the output level.
[0020]
More specifically, as a voltage as an insulation resistance detection signal indicating the resistance value of the insulation resistance appearing at the connection point p, a positive voltage component of a certain level determined by the filter 32 and the diode 31 is input to the amplifier 4. When the switching noise or the like occurs in the DC power supply system 60 and the potential appearing at the connection point p becomes a negative voltage component, the diode 4 prevents the negative voltage component from being input to the amplifier 4.
[0021]
3, when the pulse signal of FIG. 3A passes through the low-pass filter of the filter 32, it becomes the pulse signal shown in FIG. 3B. When the diode 31 in FIG. 1 is not provided (no blocking means), the output of the high-pass filter normally swings positive and negative, so that the pulse signal has a positive and negative waveform as shown in FIG. And the negative voltage component is input to the amplifier 4.
[0022]
However, as shown in FIG. 3D, by providing the diode 31 which is a blocking means in front of the amplifier 4 as in the present invention, the pulse signal in which the negative potential component is eliminated from the pulse signal of FIG. The signal is input to the amplifier 4 as a signal. Therefore, when the output of the high-pass filter becomes negative, the diode 31 prevents the negative potential component from being input to the amplifier 4.
[0023]
Therefore, even if a switching noise or the like occurs in the DC power supply system 60 and the potential appearing at the connection point p becomes a negative voltage component, the diode (blocking means) 31 inputs the negative potential component to the amplifier (amplifying means) 4. Therefore, it is possible to eliminate a possibility that a malfunction such as a malfunction or a failure of the amplifier 4 due to a negative potential component being input may occur.
[0024]
Therefore, malfunction and failure of the insulation resistance detection device 30 can be reliably prevented, so that deterioration of the insulation resistance R can be reliably detected based on the output of the insulation resistance detection device 30. As a result, the deterioration of the insulation characteristics of the insulation resistance R can be detected promptly, so that the electrical connection between the vehicle body (conductive member) 10 and the vehicle-mounted battery 6 can be reliably avoided.
[0025]
The abnormal voltage component of the voltage corresponding to the abnormal signal generated in the DC power supply system 60 is removed by the filter 32. If the abnormal voltage component that cannot be removed by the filter 32 is a negative potential component, the diode 31 becomes negative. Since the potential component is prevented from being input to the amplifier 4, even if the filter 32 is provided in a stage preceding the diode 31 and the amplifier 4, malfunction and failure of the amplifier 4 can be reliably eliminated.
[0026]
Further, in the present embodiment described above, the case where the diode 31 is used as the blocking means in the claims has been described. However, the present invention is not limited to this, and various different embodiments can be adopted. An example of another embodiment will be described below with reference to the drawing in FIG. Note that the same or corresponding portions as those described in the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.
[0027]
The basic configuration of the insulation resistance detection device 30 and the DC power supply system 60 shown in FIG. 4 is substantially the same as the basic configuration of FIG. 1, and the difference is from the configuration of the insulation resistance detection device 30 described above (see FIG. 1). The oscillation unit 50 is deleted, and the pulse signal from an external microcomputer (hereinafter, also referred to as a microcomputer) 70 is input to the input of the insulation resistance detecting device 30.
[0028]
A switch 31a is used as blocking means of the insulation resistance detecting device 30 in another embodiment, and the on / off of the switch 31a is controlled by the microcomputer 70. For example, the microcomputer 70 controls the switch 31a so that the switch 31a is turned on when the output pulse waveform is at the Lo level and turned off when the pulse waveform is at the Hi level.
[0029]
With such a configuration, even if switching noise or the like occurs in the DC power supply system 60 and the potential appearing at the connection point p becomes a negative voltage component, the switch (blocking means) 31a inputs the negative potential component to the amplifier 4. Therefore, it is possible to eliminate the possibility that a malfunction such as a malfunction or a failure of the amplifier 4 due to the input of the negative potential component occurs. Therefore, the same effect as in the above-described embodiment can be obtained.
[0030]
Furthermore, since the diode 31 rarely has a forward voltage of 0.3 V or less, the use of the switch 31a as a blocking means can cope with the case where the forward voltage is 0.3 V or less.
[0031]
Further, in the above-described embodiment, the case where the diode 31 and the switch 31a are used as the blocking means in the claims has been described. However, the present invention is not limited to this. A circuit, a photo MOS relay, a photo coupler, a CMOS analog switch, or the like can be used.
[0032]
【The invention's effect】
As described above, according to the insulation resistance detecting apparatus of the present invention, even if switching noise or the like occurs in the DC power supply system and the potential appearing at the connection point becomes a negative voltage component, the blocking means can be used. Since the negative potential component is prevented from being input to the amplifying means, it is possible to eliminate the possibility that the negative potential component is input and the amplifying means malfunctions or breaks down. Therefore, the malfunction and failure of the insulation resistance detection device can be reliably prevented, so that the deterioration of the insulation resistance can be reliably detected based on the output of the insulation resistance detection device.
[0033]
According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, an abnormal voltage component of a voltage corresponding to an abnormal signal generated in the DC power supply system is removed by the filter. If the abnormal voltage component is a negative potential component, the blocking means prevents the negative potential component from being input to the amplifying means. Therefore, even if a filter is provided in front of the blocking means and the amplifying means, the amplification is prevented. Malfunctions and failures of the means can be reliably eliminated.
[Brief description of the drawings]
FIG. 1 is a configuration diagram illustrating an example of a basic configuration of an insulation resistance detection device according to the present invention.
FIG. 2 is a circuit diagram showing an example of a filter in FIG.
FIG. 3 is a graph showing a voltage waveform in the insulation resistance detecting device.
FIG. 4 is a configuration diagram showing another embodiment of the insulation resistance detecting device.
FIG. 5 is a circuit diagram of a conventional ground fault detection system for an electric vehicle.
[Explanation of symbols]
2 Detection resistor 3 Coupling capacitor 4 Amplifier (amplification means)
10 Body body (conductive member)
31 Diode (blocking means)
31a switch (blocking means)
32 Filter 60 DC power system R Insulation resistance

Claims (2)

導電性部材に対して絶縁抵抗により電気的に絶縁される直流電源系統に対して、検出用抵抗及びカップリングコンデンサの直列回路を介してパルス信号を印加し、前記検出用抵抗と前記カップリングコンデンサとの接続点に現れる、前記絶縁抵抗の抵抗値を表す絶縁抵抗値検出信号としての電圧を、増幅手段により増幅して出力する絶縁抵抗検出装置において、
前記接続点と前記増幅手段との間に、前記電圧の負電位成分が前記増幅手段に入力されることを阻止する阻止手段を設ける
ことを特徴とする絶縁抵抗検出装置。A pulse signal is applied to a DC power supply system which is electrically insulated by an insulation resistor with respect to a conductive member through a series circuit of a detection resistor and a coupling capacitor, and the detection resistor and the coupling capacitor are applied. Appears at a connection point with, a voltage as an insulation resistance value detection signal indicating the resistance value of the insulation resistance, in an insulation resistance detection device that amplifies and outputs the result by amplifying means,
An insulation resistance detecting device, wherein a blocking means for blocking a negative potential component of the voltage from being input to the amplification means is provided between the connection point and the amplification means. 前記接続点と前記阻止手段との間に、前記直流電源系統にて発生した異常信号に応じた前記電圧の異常電圧成分を取り除くフィルタをさらに設ける
ことを特徴とする請求項１に記載の絶縁抵抗検出装置。2. The insulation resistance according to claim 1, further comprising a filter between the connection point and the blocking unit, for removing an abnormal voltage component of the voltage according to an abnormal signal generated in the DC power supply system. Detection device.
JP2003032690A 2003-02-10 2003-02-10 Insulation resistance detection device Pending JP2004245600A (en)

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Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007101424A (en) * 2005-10-06 2007-04-19 Nippon Soken Inc System mounted with insulation resistance measuring instrument, and vehicle driving system
JP2007187454A (en) * 2006-01-11 2007-07-26 Toyota Motor Corp Insulation resistance drop detector
JP2009287983A (en) * 2008-05-28 2009-12-10 Daihatsu Motor Co Ltd Insulation resistance measuring device for vehicle
WO2011074683A1 (en) * 2009-12-15 2011-06-23 株式会社ピューズ Insulation-degradation detecting device
CN102841284A (en) * 2011-06-22 2012-12-26 同济大学 On-line insulated monitoring method for high voltage of electromobile
CN103135038A (en) * 2013-02-01 2013-06-05 广州优维电子科技有限公司 Alternative current electric crosstalk and insulation fault monitoring line selection method of direct current system
CN103895523A (en) * 2012-12-25 2014-07-02 联合汽车电子有限公司 Electric system of electric automobile
JP2014134445A (en) * 2013-01-10 2014-07-24 Mitsubishi Electric Corp Arc detection apparatus
KR102061281B1 (en) 2013-08-21 2019-12-31 한온시스템 주식회사 Online insulation resistance measurement device and method in vehicle type inverter
CN110709719A (en) * 2017-12-15 2020-01-17 株式会社Lg化学 Method and apparatus for detecting battery leakage
CN111337800A (en) * 2020-03-28 2020-06-26 芜湖航翼集成设备有限公司 Intelligent insulation detection system and method special for aviation plug-in device

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007101424A (en) * 2005-10-06 2007-04-19 Nippon Soken Inc System mounted with insulation resistance measuring instrument, and vehicle driving system
JP2007187454A (en) * 2006-01-11 2007-07-26 Toyota Motor Corp Insulation resistance drop detector
JP2009287983A (en) * 2008-05-28 2009-12-10 Daihatsu Motor Co Ltd Insulation resistance measuring device for vehicle
WO2011074683A1 (en) * 2009-12-15 2011-06-23 株式会社ピューズ Insulation-degradation detecting device
JP5757877B2 (en) * 2009-12-15 2015-08-05 株式会社ピューズ Insulation deterioration detector
CN102841284A (en) * 2011-06-22 2012-12-26 同济大学 On-line insulated monitoring method for high voltage of electromobile
CN103895523A (en) * 2012-12-25 2014-07-02 联合汽车电子有限公司 Electric system of electric automobile
JP2014134445A (en) * 2013-01-10 2014-07-24 Mitsubishi Electric Corp Arc detection apparatus
CN103135038A (en) * 2013-02-01 2013-06-05 广州优维电子科技有限公司 Alternative current electric crosstalk and insulation fault monitoring line selection method of direct current system
KR102061281B1 (en) 2013-08-21 2019-12-31 한온시스템 주식회사 Online insulation resistance measurement device and method in vehicle type inverter
CN110709719A (en) * 2017-12-15 2020-01-17 株式会社Lg化学 Method and apparatus for detecting battery leakage
CN110709719B (en) * 2017-12-15 2021-12-07 株式会社Lg化学 Method and apparatus for detecting battery leakage
CN111337800A (en) * 2020-03-28 2020-06-26 芜湖航翼集成设备有限公司 Intelligent insulation detection system and method special for aviation plug-in device

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