JP4804514B2 - Non-grounded circuit insulation detector - Google Patents
Non-grounded circuit insulation detector Download PDFInfo
- Publication number
- JP4804514B2 JP4804514B2 JP2008207345A JP2008207345A JP4804514B2 JP 4804514 B2 JP4804514 B2 JP 4804514B2 JP 2008207345 A JP2008207345 A JP 2008207345A JP 2008207345 A JP2008207345 A JP 2008207345A JP 4804514 B2 JP4804514 B2 JP 4804514B2
- Authority
- JP
- Japan
- Prior art keywords
- capacitor
- resistor
- ground
- circuit
- ground potential
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Landscapes
- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
- Control Of Ac Motors In General (AREA)
- Inverter Devices (AREA)
Description
本発明は、接地電位部から絶縁して配置された非接地回路と、該接地電位部との間の絶縁レベルを検出する非接地回路の絶縁性検出装置に関する。 The present invention relates to a non-grounded circuit that is insulated from a ground potential portion and an insulation detection device for a non-ground circuit that detects an insulation level between the ground potential portion.
高電圧を出力する直流電源を備えたバッテリ駆動車両、ハイブリッド車両、燃料電池車両等の車両においては、該直流電源及び該直流電源と接続される回路を車体の接地電位部から絶縁して非接地回路とするのが一般的である。 In vehicles such as battery-powered vehicles, hybrid vehicles, and fuel cell vehicles equipped with a DC power source that outputs high voltage, the DC power source and a circuit connected to the DC power source are insulated from the ground potential portion of the vehicle body and are not grounded Generally, it is a circuit.
そして、このようにして、車両の接地電位部から絶縁して配置された非接地回路と、車両の接地電位部との間の絶縁性の劣化や地絡（非接地回路と車両の接地電位部間が短絡して、非接地回路と車両の接地電位部間の抵抗が０Ω近くまで低下した状態）を検出するための構成として、図１１に示した構成が提案されている（例えば、特許文献１参照）。 In this way, insulation deterioration between the non-ground circuit arranged insulated from the ground potential portion of the vehicle and the ground potential portion of the vehicle and a ground fault (non-ground circuit and ground potential portion of the vehicle) A configuration shown in FIG. 11 has been proposed as a configuration for detecting a short circuit between the non-ground circuit and the resistance between the ground potential portion of the vehicle and the ground potential portion of the vehicle. 1).
図１１に示した構成では、車両に搭載された高圧の直流電源１００の正側の配線が、スイッチング素子１１１と抵抗１１２とコンデンサ１１３からなる直列回路１１０を介して車両の接地電位部ＢＥと接続されている。そして、スイッチング素子１１１を導通状態としたときのコンデンサ１１３の正側の測定点１２０の電位の変化に基いて、直流電源１００を含む非接地回路と接地電位部ＢＥ間の絶縁性を検出している。 In the configuration shown in FIG. 11, the positive-side wiring of the high-voltage DC power supply 100 mounted on the vehicle is connected to the vehicle's ground potential unit BE via the series circuit 110 including the switching element 111, the resistor 112, and the capacitor 113. Has been. Then, based on the change in potential at the measurement point 120 on the positive side of the capacitor 113 when the switching element 111 is turned on, the insulation between the non-ground circuit including the DC power supply 100 and the ground potential portion BE is detected. Yes.
ここで、非接地回路と接地電位部ＢＥ間の抵抗１３０の抵抗値が高く、非接地回路と接地電位部ＢＥ間の絶縁性が保たれているときは、スイッチング素子１１１を導通状態としても、直流電源１００からコンデンサ１１３への電流Ｉ50がほとんど流れないため、測定点１２０の電位の上昇は微小なものとなる。 Here, when the resistance value of the resistor 130 between the non-ground circuit and the ground potential portion BE is high and the insulation between the non-ground circuit and the ground potential portion BE is maintained, the switching element 111 is turned on, Since the current I 50 from the DC power supply 100 to the capacitor 113 hardly flows, the rise in the potential at the measurement point 120 is minute.
それに対して、非接地回路と接地電位部ＢＥ間の絶縁性の劣化や、非接地回路と接地電位部ＢＥ間の地絡が生じて、非接地回路と接地電位部ＢＥ間の抵抗１３０が低くなったときには、直流電流１００からコンデンサ１１３に供給される電流Ｉ50が大きくなって、コンデンサ１１３が急速に充電される。そのため、測定点１２０の電位が急激に上昇する。そこで、スイッチング素子１１１を遮断状態から導通状態に切換えたときの測定点１２０の電位の上昇度合いから、非接地回路と接地電位部ＢＥ間の絶縁性を検知することができる。 On the other hand, the insulation between the non-ground circuit and the ground potential portion BE is deteriorated and a ground fault occurs between the non-ground circuit and the ground potential portion BE, so that the resistance 130 between the non-ground circuit and the ground potential portion BE is low. When this happens, the current I 50 supplied from the direct current 100 to the capacitor 113 increases and the capacitor 113 is rapidly charged. Therefore, the potential at the measurement point 120 increases rapidly. Therefore, the insulation between the non-ground circuit and the ground potential portion BE can be detected from the degree of increase in the potential at the measurement point 120 when the switching element 111 is switched from the cutoff state to the conductive state.
しかし、直流高圧電源１００の出力端子と接地電位部ＢＥ間には、一般に、ノイズ対策のために、いわゆるＹコンデンサ１０１，１０２が設けられている。そして、スイッチング素子１１１を遮断状態から導通状態に切換えたときに、Ｙコンデンサ１０１に充電されていた電荷による電流Ｉ51がコンデンサ１１３に供給されて、コンデンサ１１３の端子間電圧が上昇する。 However, generally, so-called Y capacitors 101 and 102 are provided between the output terminal of the DC high-voltage power supply 100 and the ground potential portion BE for noise countermeasures. When the switching element 111 is switched from the cut-off state to the conduction state, the current I 51 due to the charge charged in the Y capacitor 101 is supplied to the capacitor 113, and the voltage across the terminals of the capacitor 113 increases.
このように、図１１に示した構成による場合には、Ｙコンデンサ１０１からコンデンサ１１３に供給される電流によっても測定点１２０の電位が上昇するため、非接地回路と接地電位部ＢＥ間の絶縁性を精度良く検知することができないという不都合があった。
本願発明者らは、上記不都合を解消するべく、先の出願（特願２００７−３２９１８７）において、Ｙコンデンサ等の他の要素の影響を受けることない簡易な構成によって、非接地回路と車両の接地電位部間の絶縁レベルを精度良く検出することができる絶縁性検出装置を提案した。 In order to solve the above inconveniences, the inventors of the present application disclosed in the previous application (Japanese Patent Application No. 2007-329187) with a simple configuration that is not affected by other elements such as a Y capacitor, We have proposed an insulation detector that can accurately detect the insulation level between potential parts.
そして、本願発明者らは、上記先の出願による非接地回路の絶縁性検出装置についてさらに検討を行った結果、スイッチング素子を介して、直流電源の正極と負極を切替えて電気負荷に導通させるインバータを備えた非接地回路においては、接地電位部との絶縁レベルを検出精度を向上させる必要があることを知見した。 The inventors of the present invention have further studied the insulation detection device for the non-grounded circuit according to the above-mentioned previous application. As a result, an inverter that switches the positive electrode and the negative electrode of the DC power source through the switching element to conduct to the electric load. It has been found that in the non-grounded circuit having the above, it is necessary to improve the detection accuracy of the insulation level from the ground potential portion.
そこで、本発明は、スイッチング素子を介して、直流電源の正極と負極を切替えて電気負荷に導通させるインバータを備えた非接地回路と、接地電位部間の絶縁レベルの検出精度を向上させることができる非接地回路の絶縁性検出装置を提供することを目的とする。 Therefore, the present invention can improve the detection accuracy of the insulation level between the non-ground circuit including the inverter that switches the positive electrode and the negative electrode of the DC power source through the switching element to conduct to the electric load, and the ground potential portion. An object of the present invention is to provide an insulation detecting device for a non-grounded circuit.
本発明は上記目的を達成するためになされたものであり、直流電源と、該直流電源の正極と接続された正側配線と、該直流電源の負極と接続された負側配線と、該正側配線及び該負側配線と電気負荷との間に接続されて、該正側配線が該電気負荷との接続箇所に導通した正極導通状態と、該負側配線が該電気負荷との接続箇所に導通した負極導通状態とを切替えるスイッチング素子を有するインバータとを備えて、接地電位部から絶縁して配置された非接地回路と、該接地電位部との間の絶縁レベルを検出する非接地回路の絶縁性検出装置に関する。 The present invention has been made to achieve the above object, and includes a DC power supply, a positive wiring connected to the positive electrode of the DC power supply, a negative wiring connected to the negative electrode of the DC power supply, and the positive power supply. A positive conduction state in which the positive wiring is connected to the connection with the electrical load, and the negative wiring is connected to the electrical load. And an inverter having a switching element that switches between a negative conducting state and a non-grounding circuit that is insulated from the ground potential portion and a non-ground circuit that detects an insulation level between the ground potential portion The present invention relates to an insulation detection device.
そして、一端が前記正側配線に接続されて、前記非接地回路と前記接地電位部間の絶縁性を維持するための絶縁基準値よりも高い抵抗を有する第１の抵抗と、一端が前記負側配線に接続されて、前記絶縁基準値よりも高い抵抗を有する第２の抵抗と、前記第１の抵抗の他端と前記第２の抵抗の他端間に接続された第３の抵抗と、前記第１の抵抗と前記第３の抵抗との接続部である第１抵抗接続部と、前記第２の抵抗と前記第３の抵抗との接続部である第２抵抗接続部とのうちのいずれか一方を、前記接地電位部に接続する接地配線と、一端が前記接地電位部と接続されたコンデンサと、該コンデンサの他端と、前記第１抵抗接続部と前記第２抵抗接続部とのうちの前記接地配線と接続されていない方の接続部である非接地抵抗接続部との間に接続されて、該非接地抵抗接続部から該コンデンサへの充電電流と、該コンデンサから該非接地接続部への放電電流とを異なるレベルに設定する充放電設定回路と、前記インバータのスイッチング素子により、前記正極導通状態と前記負極導通状態とが切替えられているときに、前記コンデンサの端子間電圧に基づいて、前記非接地回路と前記接地電位部との間の絶縁レベルを検出する絶縁レベル検出手段とを備えたことを特徴とする。 A first resistor having one end connected to the positive side wiring and having a resistance higher than an insulation reference value for maintaining insulation between the non-grounded circuit and the ground potential portion; A second resistor connected to a side wiring and having a resistance higher than the insulation reference value; a third resistor connected between the other end of the first resistor and the other end of the second resistor; A first resistance connection portion that is a connection portion between the first resistance and the third resistance, and a second resistance connection portion that is a connection portion between the second resistance and the third resistance. Any one of the following: a ground wiring for connecting to the ground potential portion; a capacitor having one end connected to the ground potential portion; the other end of the capacitor; the first resistance connecting portion and the second resistance connecting portion And the non-ground resistance connection portion which is the connection portion which is not connected to the ground wiring. Subsequently, a charging / discharging setting circuit for setting the charging current from the non-grounded resistor connection to the capacitor and the discharging current from the capacitor to the non-grounded connection at different levels, and the switching element of the inverter, An insulation level detecting means for detecting an insulation level between the non-ground circuit and the ground potential portion based on a voltage between terminals of the capacitor when the positive electrode conductive state and the negative electrode conductive state are switched; It is provided with.
かかる本発明によれば、前記インバータと電気負荷との接続部が前記接地電位部に短絡した状態になると、前記スイッチング素子により前記正極導通状態とされたときは、前記負側配線が前記充放電設定回路を介して前記コンデンサに導通した状態となるため、前記コンデンサから前記非接地抵抗接続部に向かって放電電流が流れる。一方、前記スイッチング回路により前記負極導通状態とされたときには、前記正側配線が前記充放電回路を介して前記コンデンサに導通した状態となるため、前記非接地抵抗接続部から前記コンデンサに向かって充電電流が流れる。 According to the present invention, when the connection portion between the inverter and the electric load is short-circuited to the ground potential portion, the negative-side wiring is connected to the charge / discharge when the positive electrode is connected by the switching element. Since the capacitor is brought into conduction through the setting circuit, a discharge current flows from the capacitor toward the non-ground resistance connection portion. On the other hand, when the negative polarity conduction state is established by the switching circuit, the positive side wiring is in a state of conduction to the capacitor via the charge / discharge circuit, so that charging is performed from the non-ground resistance connection portion toward the capacitor. Current flows.
そのため、前記インバータと電気負荷との接続部が前記接地電位部に短絡した状態となったときに、前記前記スイッチング素子により前記正極導通状態と前記負極導通状態とが交互に切替えられたときには、それに応じて、前記コンデンサが放電状態と充電状態とに交互に切り換わる。 Therefore, when the connection portion between the inverter and the electric load is short-circuited to the ground potential portion, when the positive electrode conduction state and the negative electrode conduction state are alternately switched by the switching element, Accordingly, the capacitor is alternately switched between a discharged state and a charged state.
そして、前記充放電設定回路により、前記非接地抵抗接続部から前記コンデンサへの充電電流と、前記コンデンサから前記非接地抵抗接続部への放電電流が異なるレベルに設定されている。そのため、前記コンデンサの充電電流が放電電流よりも大きいときは、前記コンデンサの端子間電圧が前記正側配線が前記接地電位部に短絡したときの電圧まで次第に上昇する。また、前記コンデンサの充電電流が放電電流よりも小さいときには、前記コンデンサの端子間電圧が前記負側配線が前記接地電位部に短絡したときの電圧まで次第に低下する。 The charging / discharging setting circuit sets the charging current from the non-grounded resistor connection to the capacitor and the discharging current from the capacitor to the non-grounded resistance connection at different levels. Therefore, when the charging current of the capacitor is larger than the discharging current, the voltage between the terminals of the capacitor gradually increases to the voltage when the positive wiring is short-circuited to the ground potential portion. Further, when the charging current of the capacitor is smaller than the discharging current, the voltage between the terminals of the capacitor gradually decreases to the voltage when the negative wiring is short-circuited to the ground potential portion.
そして、これらの場合には、詳細は後述するが、前記インバータと電気負荷との接続部が前記接地電位部と短絡したことを、前記正側配線が前記接地電位部と短絡したとき、又は前記負側配線が前記接地電位部に短絡したときと同じ判定条件で検出することができる。そのため、前記第３の抵抗の端子間電圧に基づいて、前記インバータ及び電気負荷の接続部が前記接地電位部に短絡したときの判定条件によって、前記非接地回路と前記接地電位部との間の短絡を検出するときよりも、前記非接地回路と前記接地電位部との間の短絡を検出精度を高めることができる。 In these cases, as will be described in detail later, the connection between the inverter and the electric load is short-circuited to the ground potential portion, the positive wiring is short-circuited to the ground potential portion, or the Detection can be performed under the same determination conditions as when the negative wiring is short-circuited to the ground potential portion. Therefore, based on the voltage between the terminals of the third resistor, depending on the determination condition when the connection portion of the inverter and the electric load is short-circuited to the ground potential portion, between the non-ground circuit and the ground potential portion The detection accuracy of the short circuit between the non-ground circuit and the ground potential unit can be improved as compared with the case of detecting the short circuit.
また、前記充放電設定回路は、前記コンデンサと前記非接地抵抗接続部との間に接続された第５の抵抗と、第４の抵抗とダイオードとを直列に接続して構成され、前記第５の抵抗と並列に接続された直列回路とを備えたことを特徴とする。 The charge / discharge setting circuit is configured by connecting a fifth resistor, a fourth resistor, and a diode connected in series between the capacitor and the non-grounded resistor connection portion, and the fifth resistor. And a series circuit connected in parallel.
かかる本発明によれば、前記ダイオードの順方向に電圧が印加されたときは、前記充放電設定回路を介して通電するときの抵抗は、前記第４の抵抗と前記第５の抵抗との並列合成抵抗となる。一方、前記ダイオードの逆方向に電圧が印加されたときには、前記直列回路側には電流は流れないため、前記充放電設定回路を介して通電するときの抵抗は、前記第５の抵抗分のみとなる。そのため、前記非接地抵抗接続部から前記コンデンサへの充電電流と、前記コンデンサから前記非接地抵抗接続部への放電電流の大きさとを、異なるレベルに設定することができる。 According to the present invention, when a voltage is applied in the forward direction of the diode, a resistance when energizing through the charge / discharge setting circuit is a parallel of the fourth resistance and the fifth resistance. Combined resistance. On the other hand, when a voltage is applied in the reverse direction of the diode, no current flows through the series circuit side. Therefore, the resistance when energizing through the charge / discharge setting circuit is only the fifth resistance. Become. For this reason, the charging current from the non-ground resistance connection portion to the capacitor and the magnitude of the discharge current from the capacitor to the non-ground resistance connection portion can be set to different levels.
また、アノード側が前記第２抵抗接続部に接続されると共に、カソード側が前記第１抵抗接続部に接続されて、前記第３の抵抗の端子間電圧を前記絶縁レベル検出手段の許容入力電圧範囲内に維持するツェナーダイオードを備えたことを特徴とする。 The anode side is connected to the second resistance connection portion, and the cathode side is connected to the first resistance connection portion, so that the voltage across the terminals of the third resistance is within the allowable input voltage range of the insulation level detection means. It is characterized by comprising a Zener diode to be maintained at
かかる本発明によれば、前記絶縁レベル検出手段による検出精度を向上させるためには、前記非接地回路と前記接地電位部との間の絶縁レベルの判定閾値付近での前記コンデンサの端子間電圧の変動幅を大きくする必要がある。そこで、詳細は後述するが、前記ツェナーダイオードを備えることによって、絶縁レベルの判定閾値付近での変化に対する前記コンデンサの端子間電圧の変動幅を大きくしつつ、前記絶縁レベル検出手段への入力電圧を前記絶縁レベル検出手段の許容入力電圧範囲内に維持することができる。 According to the present invention, in order to improve the detection accuracy by the insulation level detection means, the voltage between the terminals of the capacitor near the insulation level determination threshold value between the non-ground circuit and the ground potential portion is determined. It is necessary to increase the fluctuation range. Therefore, as will be described in detail later, by providing the Zener diode, the input voltage to the insulation level detection means is increased while increasing the fluctuation range of the voltage across the capacitor with respect to the change in the vicinity of the determination threshold value of the insulation level. It can be maintained within the allowable input voltage range of the insulation level detection means.
また、前記充放電設定回路は、前記コンデンサの前記非接地抵抗接続部側の端子と前記非接地抵抗接続部との間に、前記非接地抵抗接続部から前記コンデンサへの向きを順方向として接続された第１のダイオードと、第６の抵抗と第２のダイオードとを直列に接続して構成され、該第２のダイオードの順方向を前記非接地抵抗接続部から前記接地電位部への向きとして、前記コンデンサと並列に接続された直列回路とを備えたことを特徴とする。 Further, the charge / discharge setting circuit is connected between the terminal on the non-ground resistance connection portion side of the capacitor and the non-ground resistance connection portion with the direction from the non-ground resistance connection portion to the capacitor as a forward direction. The first diode, the sixth resistor, and the second diode are connected in series, and the forward direction of the second diode is directed from the non-ground resistance connection portion to the ground potential portion. And a series circuit connected in parallel with the capacitor.
かかる本発明によれば、前記第１のダイオードの順方向に電圧が印加されたときは、前記非接地抵抗接続部から前記第１のダイオードを介して供給される電流により、前記コンデンサが充電され、このときの充電電流は前記第１の抵抗及び前記第３の抵抗の抵抗値により大きさが変化する。一方、前記第１のダイオードの逆方向に電圧が印加されたときには、前記コンデンサから前記非接地抵抗接続部への電流の流通が前記第１のダイオードにより遮断されるため、前記コンデンサから前記第２のダイオード及び前記第６の抵抗を介して、前記非接地抵抗接続部の電位まで放電電流が流れる。そのため、前記第１の抵抗及び前記第２の抵抗と前記第６の抵抗の抵抗値の設定により、前記コンデンサの充電電流と放電電流を異なるレベルに設定することができる。 According to the present invention, when a voltage is applied in the forward direction of the first diode, the capacitor is charged by the current supplied through the first diode from the non-grounded resistance connection portion. The magnitude of the charging current at this time varies depending on the resistance values of the first resistor and the third resistor. On the other hand, when a voltage is applied in the reverse direction of the first diode, the flow of current from the capacitor to the non-grounded resistance connection portion is interrupted by the first diode, so that the second from the capacitor. A discharge current flows through the diode and the sixth resistor to the potential of the non-ground resistance connection portion. Therefore, the charging current and discharging current of the capacitor can be set to different levels by setting the resistance values of the first resistor, the second resistor, and the sixth resistor.
また、アノード側を前記接地電位部側として前記コンデンサと並列に接続され、前記コンデンサの端子間電圧を前記絶縁レベル検出手段の許容入力範囲内に維持するツェナーダイオードを備えたことを特徴とする。 In addition, a Zener diode is provided which is connected in parallel with the capacitor with the anode side as the ground potential portion side, and maintains a voltage between terminals of the capacitor within an allowable input range of the insulation level detection means.
かかる本発明によれば、前記絶縁レベル検出手段による検出精度を向上させるためには、前記非接地回路と前記接地電位部との間の絶縁レベルの判定閾値付近での前記コンデンサの端子間電圧の変動幅を大きくする必要がある。そこで、詳細は後述するが、前記ツェナーダイオードを備えることによって、絶縁レベルの判定閾値付近での変化に対する前記コンデンサの端子間電圧の変動幅を大きくしつつ、前記絶縁レベル検出手段への入力電圧を前記絶縁レベル検出手段の許容入力電圧範囲内に維持することができる。 According to the present invention, in order to improve the detection accuracy by the insulation level detection means, the voltage between the terminals of the capacitor near the insulation level determination threshold value between the non-ground circuit and the ground potential portion is determined. It is necessary to increase the fluctuation range. Therefore, as will be described in detail later, by providing the Zener diode, the input voltage to the insulation level detection means is increased while increasing the fluctuation range of the voltage across the capacitor with respect to the change in the vicinity of the determination threshold value of the insulation level. It can be maintained within the allowable input voltage range of the insulation level detection means.
また、前記充放電設定回路は、前記非接地抵抗接続部から前記コンデンサへの充電電流を、前記コンデンサから前記非接地抵抗接続部への放電電流よりも大きく設定し、前記絶縁レベル検出手段は、前記コンデンサの端子間電圧が、第１の所定電圧以上になったときに、前記負側配線と前記接地電位部間、又は前記インバータと電気負荷との接続部と前記接地電位部間が短絡状態にあると判断することを特徴とする。 Further, the charge / discharge setting circuit sets a charging current from the non-ground resistance connection portion to the capacitor to be larger than a discharge current from the capacitor to the non-ground resistance connection portion, and the insulation level detection means includes: When the voltage between the terminals of the capacitor becomes equal to or higher than a first predetermined voltage, a short circuit is established between the negative wiring and the ground potential portion or between the connection portion of the inverter and the electric load and the ground potential portion. It is characterized by judging that it exists in.
かかる本発明において、前記負側配線と前記接地電位部とが短絡した状態になると、前記非接地抵抗接続部から前記充放電設定回路を介して前記コンデンサに充電電流が流れ、前記コンデンサの端子間電圧が上昇する。また、前記インバータと電気負荷との接続部が前記接地電位部に短絡した状態になったときにも、前記コンデンサの充電電流が放電電流よりも大きく設定されているため、前記コンデンサの端子間電圧が、前記負側配線と前記接地電位部とが短絡した状態と同じレベルまで上昇する。そのため、前記絶縁レベル検出手段は、前記コンデンサの端子間電圧が前記第１の所定電圧以上となったときに、前記負側配線と前記接地電位部間又は前記インバータと電気負荷との接続部と前記接地電位部間が短絡状態にあると判断することができる。 In the present invention, when the negative wiring and the ground potential portion are short-circuited, a charging current flows from the non-ground resistance connection portion to the capacitor via the charge / discharge setting circuit, and between the terminals of the capacitor. The voltage rises. Further, even when the connection portion between the inverter and the electric load is short-circuited to the ground potential portion, the charging current of the capacitor is set to be larger than the discharging current. However, it rises to the same level as the state where the negative wiring and the ground potential portion are short-circuited. Therefore, when the voltage between the terminals of the capacitor becomes equal to or higher than the first predetermined voltage, the insulation level detection means is connected between the negative wiring and the ground potential part or a connection part between the inverter and the electric load. It can be determined that the ground potential portions are short-circuited.
また、前記充放電設定回路は、前記コンデンサから前記非接地抵抗接続部への放電電流を、前記非接地抵抗接続部から前記コンデンサへの充電電流よりも大きく設定し、前記絶縁レベル検出手段は、前記コンデンサの端子間電圧が、第２の所定電圧以下になったときに、前記正側配線と前記接地電位部間、又は前記インバータと電気負荷との接続部と前記接地電位部間が短絡状態にあると判断することを特徴とする。 Further, the charge / discharge setting circuit sets a discharge current from the capacitor to the non-ground resistance connection portion larger than a charge current from the non-ground resistance connection portion to the capacitor, and the insulation level detection means includes: When the voltage between the terminals of the capacitor becomes equal to or lower than a second predetermined voltage, a short circuit is established between the positive wiring and the ground potential portion or between the connection portion of the inverter and the electric load and the ground potential portion. It is characterized by judging that it exists in.
かかる本発明において、前記正側配線と前記接地電位部とが短絡した状態になると、前記コンデンサから前記充放電設定回路を介して前記非接地抵抗接続部の電位まで放電電流が流れ、前記コンデンサの端子間電圧が低下する。また、前記インバータと電気負荷との接続部が前記接地電位部に短絡した状態になったときにも、前記コンデンサの放電電流が充電電流よりも大きく設定されているため、前記コンデンサの端子間電圧が、前記正側配線と前記接地電位部とが短絡した状態と同じレベルまで低下する。そのため、前記絶縁レベル検出手段は、前記コンデンサの端子間電圧が前記第２の所定電圧以下となったときに、前記正側配線と前記接地電位部間又は前記インバータと電気負荷との接続部と前記接地電位部間が短絡状態にあると判断することができる。 In the present invention, when the positive-side wiring and the ground potential portion are short-circuited, a discharge current flows from the capacitor to the potential of the non-ground resistance connection portion via the charge / discharge setting circuit. Voltage between terminals decreases. In addition, even when the connection portion of the inverter and the electric load is short-circuited to the ground potential portion, the discharge current of the capacitor is set to be larger than the charging current. However, it drops to the same level as in the state where the positive wiring and the ground potential portion are short-circuited. Therefore, when the voltage between the terminals of the capacitor becomes equal to or lower than the second predetermined voltage, the insulation level detection means is connected between the positive wiring and the ground potential portion or a connection portion between the inverter and the electric load. It can be determined that the ground potential portions are short-circuited.
本発明の実施形態について、図１〜図１０を参照して説明する。 An embodiment of the present invention will be described with reference to FIGS.
先ず、本発明の前提となる非接地回路の絶縁性検出装置の基本的な構成について、図１〜図５を参照して説明する。 First, a basic configuration of an insulation detecting device for a non-grounded circuit which is a premise of the present invention will be described with reference to FIGS.
図１に示した非接地回路の絶縁性検出装置２０（以下、単に絶縁性検出装置２０という）は、非接地回路１０と車両の接地電位部ＢＥとの間の絶縁レベルを検出するものである。非接地回路１０は、燃料電池スタック等の高電圧ＶM（例えば数百Ｖ）を出力する直流電源１２と、直流電源１２とモータ４０間に接続されて直流電源１２から出力される電圧ＶMを正側のトランジスタＱ11，Ｑ21，Ｑ31（本発明のスイッチング素子に相当する）及び負側のトランジスタＱ12，Ｑ22，Ｑ32（本発明のスイッチング素子に相当する）をスイッチングすることにより、モータ４０に３相（Ｕ相，Ｖ相，Ｗ相）の駆動電圧を出力するインバータ１１とを有して、接地電位部ＢＥから絶縁して配置されている。なお、絶縁性検出装置２０は、車両のＥＣＵ（Electronic Control Unit）の一部として構成されている。 The non-grounded circuit insulation detection device 20 shown in FIG. 1 (hereinafter simply referred to as insulation detection device 20) detects the insulation level between the non-ground circuit 10 and the vehicle ground potential portion BE. . The non-ground circuit 10 is connected between the DC power source 12 that outputs a high voltage VM (for example, several hundreds V) such as a fuel cell stack, and the voltage VM that is connected between the DC power source 12 and the motor 40 and output from the DC power source 12. By switching the side transistors Q 11 , Q 21 , Q 31 (corresponding to the switching element of the present invention) and the negative side transistors Q 12 , Q 22 , Q 32 (corresponding to the switching element of the present invention), The motor 40 includes an inverter 11 that outputs three-phase (U-phase, V-phase, and W-phase) drive voltages, and is arranged insulated from the ground potential portion BE. The insulation detection device 20 is configured as a part of an ECU (Electronic Control Unit) of the vehicle.
そして、絶縁性検出装置２０は、オペアンプ２６と、直流電源１２の正極と接続された正側配線（図中ＰＯＧと接続された配線）とオペアンプ２６との間に接続された第１の抵抗２１と、直流電源１２の負極と接続された負側配線（図中ＮＥＧと接続された配線）とオペアンプ２６との間に接続された第２の抵抗２２と、第１の抵抗２１と第２の抵抗２２との間に接続された第３の抵抗２３、第２の抵抗２２と第３の抵抗２３の接続部（本発明の第２抵抗接続部に相当する）を接地電位部ＢＥと接続する接地配線と、第３の抵抗２３と並列に接続された平滑用コンデンサ２５と、オペアンプ２６の出力端子と接続されたマイクロコンピュータ３０とにより構成されている。 The insulation detection device 20 includes an operational amplifier 26, a first resistor 21 connected between the operational amplifier 26 and a positive-side wiring (wiring connected to POG in the drawing) connected to the positive electrode of the DC power supply 12. The second resistor 22 connected between the negative line connected to the negative electrode of the DC power supply 12 (the line connected to NEG in the figure) and the operational amplifier 26, the first resistor 21 and the second resistor The third resistor 23 connected between the resistor 22 and the connecting portion of the second resistor 22 and the third resistor 23 (corresponding to the second resistor connecting portion of the present invention) is connected to the ground potential portion BE. It is composed of a ground wiring, a smoothing capacitor 25 connected in parallel with the third resistor 23, and a microcomputer 30 connected to the output terminal of the operational amplifier 26.
マイクロコンピュータ３０は、所定の制御用プログラムを実行することにより、非接地回路１０と接地電位部ＢＥ間の絶縁レベルを検出する絶縁レベル検出手段３１として機能する。なお、マイクロコンピュータ３０とオペアンプ２６は、直流電源１２とは別に設けられた出力電圧がＶMよりも低いＶccである直流電源（図示しない）からの出力電力によって作動する。 The microcomputer 30 functions as an insulation level detection means 31 that detects an insulation level between the non-ground circuit 10 and the ground potential portion BE by executing a predetermined control program. Incidentally, the microcomputer 30 and the operational amplifier 26 is operated by the output power from the DC power supply output voltage is provided separately from the DC power source 12 is lower V cc than VM (not shown).
ここで、第１の抵抗２１の抵抗値Ｒ1と、第２の抵抗２２の抵抗値Ｒ2は、非接地回路１０の接地電位部ＢＥに対する絶縁抵抗の基準値（例えば、５００Ω／Ｖ以上）以上の絶縁レベルを確保するために、ＭΩレベルに設定されている。ここで、非接地回路１０と接地電位部ＢＥ間の地絡（非接地回路と車両の接地電位部間が短絡して、非接地回路と車両の接地電位部間の抵抗が０Ω近くまで低下した状態）が生じていないときは、第３の抵抗２３の端子間電圧Ｖoutは、以下の式（１）により近似される。 Here, the resistance value R1 of the first resistor 21 and the resistance value R2 of the second resistor 22 are not less than a reference value (for example, 500 Ω / V or more) of the insulation resistance with respect to the ground potential portion BE of the non-ground circuit 10. In order to ensure the insulation level, the MΩ level is set. Here, the ground fault between the non-ground circuit 10 and the ground potential portion BE (the short circuit between the non-ground circuit and the vehicle ground potential portion causes the resistance between the non-ground circuit and the vehicle ground potential portion to drop to near 0Ω. When the state does not occur, the inter-terminal voltage Vout of the third resistor 23 is approximated by the following equation (1).
但し、Ｖout：第３の抵抗２３の端子間電圧、Ｒ1：第１の抵抗２１の抵抗値、Ｒ2：第２の抵抗２２の抵抗値、Ｒ3：第３の抵抗２３の抵抗値、ＶM：直流電源１２の出力電圧。 Where V out is the voltage across the third resistor 23, R 1 is the resistance value of the first resistor 21, R 2 is the resistance value of the second resistor 22, R 3 is the resistance value of the third resistor 23, and VM is The output voltage of the DC power supply 12.
そして、オペアンプ２６への入力電圧Ｖoutは、後述する負側配線の地絡を生じたときに最大となり、このときのＶoutは、以下の式（２）により近似される。 The input voltage Vout to the operational amplifier 26 becomes maximum when a ground fault in a negative side wiring described later occurs, and Vout at this time is approximated by the following equation (2).
そのため、上記式（２）によるＶoutが、オペアンプ２６の許容入力電圧範囲の上限であるＶccを超えないように、第１の抵抗２１の抵抗値Ｒ1と第３の抵抗２３の抵抗値Ｒ3が設定されている。そして、絶縁レベル検出手段３１は、オペアンプ２６から出力されるＶoutの増幅出力Ｖrefを入力して、Ｖoutのレベルを認識する。 Therefore, the resistance value R1 of the first resistor 21 and the resistance value R3 of the third resistor 23 are set so that Vout according to the above equation (2) does not exceed Vcc which is the upper limit of the allowable input voltage range of the operational amplifier 26. Is set. The insulation level detection means 31 receives the amplified output V ref of V out output from the operational amplifier 26 and recognizes the level of V out .
次に、図２を参照して、非接地回路１０の負側配線と接地電位部ＢＥ間の地絡（以下、負側地絡という）の検出について説明する。図２（ａ）を参照して、非接地回路１０の負側配線と接地電位部ＢＥ間が抵抗４０により地絡（抵抗４０の抵抗値Ｒt1≪第２の抵抗２２の抵抗値Ｒ2）した場合、オペアンプ２６への入力電圧Ｖoutは、以下の式（３）により近似される。 Next, detection of a ground fault between the negative side wiring of the non-ground circuit 10 and the ground potential part BE (hereinafter referred to as a negative side ground fault) will be described with reference to FIG. Referring to FIG. 2A, a ground fault occurs between the negative wiring of the non-ground circuit 10 and the ground potential portion BE due to the resistor 40 (the resistance value Rt1 of the resistor 40 << the resistance value R2 of the second resistor 22). The input voltage Vout to the operational amplifier 26 is approximated by the following equation (3).
但し、Ｒt1：非接地回路１０の負側配線と接地電位部ＢＥ間の抵抗値。 Rt1: A resistance value between the negative side wiring of the non-ground circuit 10 and the ground potential portion BE.
上記式（３）から、非接地回路１０の負側配線と接地電位部ＢＥ間の抵抗４０の抵抗値Ｒt1が小さくなるに従って、オペアンプ２６への入力電圧Ｖoutが高くなることがわかる。そして、Ｒt1≒０ΩのときはＶoutは上記式（２）で示した電圧となる。 From the above equation (3), it can be seen that the input voltage Vout to the operational amplifier 26 increases as the resistance value Rt1 of the resistor 40 between the negative side wiring of the non-ground circuit 10 and the ground potential portion BE decreases. When Rt1≈0Ω, Vout is the voltage expressed by the above equation (2).
図２（ｂ）は、非接地回路１０の負側配線と接地電位部ＢＥ間の抵抗４０の抵抗値Ｒt1と、オペアンプ２６への入力電圧Ｖoutとの関係を、抵抗値Ｒt1を横軸とし、入力電圧Ｖoutを縦軸として示した近似グラフである。絶縁レベル検出手段３１は、図２（ｂ）に示したように、オペアンプ２６への入力電圧Ｖoutが、非接地回路１０と接地電位部ＢＥ間の絶縁抵抗の基準値Ｒth_1に対応した電圧Ｖth_1（本発明の第１の所定電圧に相当する）以上になったときに、非接地回路１０の負側配線と接地電位部ＢＥ間の地絡が生じていると判断する。なお、図２（ｂ）のＶtypは、非接地回路１０と接地電位部ＢＥ間の地絡が生じていない場合における非接地回路１０と接地電位部ＢＥ間の抵抗値の典型値である。 FIG. 2B shows the relationship between the resistance value Rt1 of the resistor 40 between the negative side wiring of the non-ground circuit 10 and the ground potential portion BE and the input voltage Vout to the operational amplifier 26, with the resistance value Rt1 as the horizontal axis. FIG. 6 is an approximate graph showing the input voltage V out as a vertical axis. As shown in FIG. 2B, the insulation level detection means 31 is such that the input voltage Vout to the operational amplifier 26 is a voltage Vth_1 corresponding to the reference value Rth_1 of the insulation resistance between the non-ground circuit 10 and the ground potential portion BE. When the voltage becomes equal to or higher (corresponding to the first predetermined voltage of the present invention), it is determined that a ground fault has occurred between the negative wiring of the non-ground circuit 10 and the ground potential portion BE. Note that V typ in FIG. 2B is a typical value of the resistance value between the non-ground circuit 10 and the ground potential portion BE when no ground fault occurs between the non-ground circuit 10 and the ground potential portion BE.
次に、図３を参照して、非接地回路１０の正側配線と接地電位部ＢＥ間の地絡（以下、正側地絡という）の検出について説明する。図３（ａ）を参照して、非接地回路１０の正側配線と接地電位部ＢＥ間が抵抗４１により地絡（抵抗４１の抵抗値Ｒt2≪第１の抵抗２１の抵抗値Ｒ1）した場合、第３の抵抗２３の端子間電圧入力電圧Ｖoutは、以下の式（４）により表される。 Next, detection of a ground fault between the positive wiring of the non-ground circuit 10 and the ground potential part BE (hereinafter referred to as a positive ground fault) will be described with reference to FIG. Referring to FIG. 3A, a ground fault occurs between the positive wiring of the non-ground circuit 10 and the ground potential portion BE due to the resistor 41 (resistance value Rt2 of the resistor 41 << resistance value R1 of the first resistor 21). The inter-terminal voltage input voltage V out of the third resistor 23 is expressed by the following equation (4).
但し、Ｒt2：非接地回路１０の正側配線と接地電位部ＢＥ間の抵抗値。 Rt2: resistance value between the positive side wiring of the non-ground circuit 10 and the ground potential portion BE.
上記式（４）から、非接地回路１０の正側配線と接地電位部ＢＥ間の抵抗４１の抵抗値Ｒt2が小さくなるに従って、オペアンプ２６への入力電圧Ｖoutが低くなることがわかる。そして、抵抗値Ｒt2≒０Ωのときに、Ｖoutは０Ｖとなる。 From the above equation (4), it can be seen that the input voltage Vout to the operational amplifier 26 decreases as the resistance value Rt2 of the resistor 41 between the positive side wiring of the non-ground circuit 10 and the ground potential portion BE decreases. When the resistance value Rt2≈0Ω, Vout becomes 0V.
図３（ｂ）は、非接地回路１０の正側配線と接地電位部ＢＥ間の抵抗４１の抵抗値Ｒt2と、第３の抵抗２３の端子間電圧Ｖoutとの関係を、Ｒt2を横軸とし、Ｖoutを縦軸として示した近似グラフである。絶縁レベル検出手段３１は、図３（ｂ）に示したように、第３の抵抗２３の端子間電圧Ｖoutが、非接地回路１０と接地電位部ＢＥ間の絶縁抵抗の基準値Ｒth_2に対応した電圧Ｖth_2（本発明の第２の所定電圧に相当する）以下になったときに、非接地回路１０の正側配線と接地電位部ＢＥ間の地絡が生じていると判断する。 FIG. 3B shows the relationship between the resistance value Rt2 of the resistor 41 between the positive wiring of the non-ground circuit 10 and the ground potential portion BE and the voltage Vout between the terminals of the third resistor 23, and Rt2 is plotted on the horizontal axis. And V out is an approximate graph showing the vertical axis. As shown in FIG. 3B, the insulation level detection means 31 is such that the inter-terminal voltage Vout of the third resistor 23 corresponds to the reference value Rth_2 of the insulation resistance between the non-ground circuit 10 and the ground potential portion BE. It is determined that a ground fault has occurred between the positive wiring of the non-ground circuit 10 and the ground potential portion BE when the voltage becomes equal to or less than the voltage Vth_2 (corresponding to the second predetermined voltage of the present invention).
次に、図４及び図５を参照して、非接地回路１０のインバータ１１とモータ４０間の接続部と接地電位部ＢＥと間の地絡（以下、３相地絡という）の検出について説明する。図４は、インバータ１１とモータ４０のＵ相間の配線が抵抗４２を介して接地電位部ＢＥに地絡した状態を示している。 Next, with reference to FIGS. 4 and 5, detection of a ground fault (hereinafter referred to as a three-phase ground fault) between the connection part between the inverter 11 and the motor 40 of the non-ground circuit 10 and the ground potential part BE will be described. To do. FIG. 4 shows a state in which the wiring between the U phase of the inverter 11 and the motor 40 is grounded to the ground potential portion BE through the resistor 42.
図４において、Ｕ相については、インバータ１１のトランジスタＱ11がＯＮ（導通状態）であってトランジスタＱ12がＯＦＦ（遮断状態）である正極導通状態のときに、非接地回路１０の正側配線がトランジスタＱ11を介して接地電位部ＢＥに地絡する。また、インバータ１１のトランジスタＱ12がＯＮであってトランジスタＱ11がＯＦＦである負極導通状態のときに、非接地回路１０の負側配線がトランジスタＱ12を介して接地電位部ＢＥに地絡する。同様にして、Ｖ相についてはトランジスタＱ21，Ｑ22により、また、Ｗ相についてはトランジスタＱ31，Ｑ32により、正極導通状態と負極導通状態とが切替えられて、負側配線又は正側配線が接地電位部ＢＥに地絡する。 In FIG. 4, for the U phase, when the transistor Q 11 of the inverter 11 is ON (conducting state) and the transistor Q 12 is OFF (cut-off state) and is in the positive conducting state, the positive side wiring of the non-ground circuit 10 There is ground to ground potential portion bE through the transistor Q 11. The transistor Q 11 transistors Q 12 is a ON of the inverter 11 is at the negative electrode conductive state is OFF, the negative side wiring ungrounded circuit 10 is a ground fault to the ground potential portion BE through the transistor Q 12 . Similarly, the positive phase conduction state and the negative polarity conduction state are switched by the transistors Q 21 and Q 22 for the V phase and by the transistors Q 31 and Q 32 for the W phase, so that the negative side wiring or the positive side wiring is switched. Is grounded to the ground potential portion BE.
ここで、図５は、横軸を共通の時間軸（ｔ）として、インバータ１１とモータ４０のＵ相間の配線が抵抗４２を介して接地電位部ＢＥに地絡した状態で、トランジスタＱ11，Ｑ12をスイッチングして正極導通状態と負極導通状態とを切替えたときの、第３の抵抗４２の端子間電圧Ｖoutの変化を示したものである。 Here, FIG. 5, the horizontal axis common time axis as (t), in a state where the wiring between the U-phase of the inverter 11 and the motor 40 is grounded to the ground potential portion BE via a resistor 42, a transistor Q 11, the Q 12 and switching when switching the positive electrode conducting state and the negative conducting state, shows the change in the terminal voltage V out of the third resistor 42.
図５の（ａ）はトランジスタＱ11の状態（ＯＮ／ＯＦＦ）を示し、図５の（ｂ）はトランジスタＱ12の状態（ＯＮ／ＯＦＦ）を示している。図５では、ｔ10〜ｔ11，ｔ12〜ｔ13，ｔ14〜ｔ15，ｔ16〜ｔ17，ｔ18〜ｔ19，ｔ20〜ｔ21，ｔ22〜ｔ23の各期間が正極導通状態（トランジスタＱ11がＯＮ，トランジスタＱ12がＯＦＦ）となっている。また、ｔ11〜ｔ12，ｔ13〜ｔ14，ｔ15〜ｔ16，ｔ17〜ｔ18，ｔ19〜ｔ20，ｔ21〜ｔ22の各期間が負極導通状態（トランジスタＱ12がＯＮ，トランジスタＱ22がＯＦＦ）となっている。 (A) of FIG. 5 shows the state of the transistor Q 11 (ON / OFF), (b) in FIG. 5 shows the state of the transistor Q 12 (ON / OFF). In Figure 5, the period of t 10 ~t 11, t 12 ~t 13, t 14 ~t 15, t 16 ~t 17, t 18 ~t 19, t 20 ~t 21, t 22 ~t 23 is positive It is in a conducting state (transistor Q 11 is ON and transistor Q 12 is OFF). In addition, each period of t 11 to t 12 , t 13 to t 14 , t 15 to t 16 , t 17 to t 18 , t 19 to t 20 , t 21 to t 22 is in a negative polarity conducting state (transistor Q 12 is ON) , has become the transistor Q 22 is OFF) a.
また、図５の（ｃ）は、Ｒ1＝Ｒ2（≫Ｒ3）、抵抗４３の抵抗値Ｒt3≒０Ωであって、平滑用コンデンサ２５の容量Ｃ1が０pFであるときの第３の抵抗２３の端子間電圧Ｖoutの変化を示したものである。さらに、図５（ｄ）は、Ｒ1＝Ｒ2（≫Ｒ3）、抵抗４２の抵抗値Ｒt3≒０Ωであって、平滑用コンデンサ２５の容量Ｃ1が大（モータ４０に対する駆動電圧を平滑化するために、該駆動電圧の周波数に応じて設定される）であるときの第３の抵抗２３の端子間電圧Ｖoutの変化を示したものである。 5C shows the terminal of the third resistor 23 when R1 = R2 (>> R3), the resistance value Rt3≈0Ω of the resistor 43, and the capacitance C1 of the smoothing capacitor 25 is 0 pF. It shows the change in the inter-voltage Vout . Further, FIG. 5 (d) is, R1 = R2 (»R3), resistor 4 a second resistance value Rt3 ≒ 0 .OMEGA, since the capacitance C1 of the smoothing capacitor 25 is for smoothing the driving voltage for large (motor 40 The change in the voltage Vout between the terminals of the third resistor 23 when the frequency is set in accordance with the frequency of the drive voltage is shown.
この場合、平滑用コンデンサ２５の容量Ｃ1が０pFであるときは、正極導通状態であるときに非接地回路１０の正側配線がトランジスタＱ11を介して接地電位部ＢＥに地絡し、第３の抵抗２３の端子間電圧Ｖoutが０Ｖとなる。また、負極導通状態であるときに、非接地回路１０の負側配線がトランジスタＱ12を介して接地電位部ＢＥに地絡し、第３の抵抗２３の端子間電圧Ｖoutが、地絡が生じていないときの電圧Ｖtypの２倍（Ｖtpy×２）となる。 In this case, when the capacitance C1 of the smoothing capacitor 25 is 0pF is to positive-side wiring is a ground fault to the ground potential portion BE through the transistor Q 11 of the non-grounding circuit 10 when a positive conductive, third The voltage V out between the terminals of the resistor 23 becomes 0V. Further, when a negative electrode conductive state, the negative side wiring ungrounded circuit 10 is grounded to the ground potential portion BE through the transistor Q 12, the terminal voltage V out of the third resistor 23, a ground fault It becomes twice the voltage V typ when it does not occur (V tpy × 2).
そして、平滑用コンデンサ２５の容量Ｃ1を増大させると、第３の抵抗２３の端子間電圧ＶoutがＶtyp付近に平滑化されて、インバータ１１とモータ４０間の配線と接地電位部ＢＥとの間で地絡が生じていない場合と同じ状況となる。そのため、絶縁レベル検出手段３１は、インバータ１１とモータ４０間の配線と接地電位部ＢＥとの間で地絡が生じていることを検知することができない。 When the capacitance C1 of the smoothing capacitor 25 is increased, the inter-terminal voltage Vout of the third resistor 23 is smoothed near V typ , and the wiring between the inverter 11 and the motor 40 and the ground potential portion BE are reduced. The situation is the same as when no ground fault has occurred. Therefore, the insulation level detection means 31 cannot detect that a ground fault has occurred between the wiring between the inverter 11 and the motor 40 and the ground potential portion BE.
そこで、第１の抵抗２１の抵抗値Ｒ1と第２の抵抗２２の抵抗値Ｒ2を異なる値に設定することにより、インバータ１１とモータ４０間の配線と接地電位部ＢＥとの間で地絡が生じていることを、該地絡が生じていないときと区別して検出することができる。 Therefore, by setting the resistance value R1 of the first resistor 21 and the resistance value R2 of the second resistor 22 to different values, a ground fault occurs between the wiring between the inverter 11 and the motor 40 and the ground potential portion BE. The occurrence can be detected separately from the case where the ground fault does not occur.
図５（ｅ）は、第２の抵抗２２の抵抗値Ｒ2が第１の抵抗２１の抵抗値Ｒ1の３倍（Ｒ2＝３×Ｒ1）、抵抗４３の抵抗値Ｒt3≒０Ωであって、平滑用コンデンサ２５の容量Ｃ1が０pFであるときの第３の抵抗２３の端子間電圧Ｖoutの変化を示したものである。また、図５（ｆ）は、第２の抵抗２２の抵抗値Ｒ2が第１の抵抗２１の抵抗値Ｒ1の３倍（Ｒ2＝３×Ｒ1）、抵抗４３の抵抗値Ｒt3≒０Ωであって、平滑用コンデンサ２５の容量Ｃ1が大であるときの第３の抵抗２３の端子間電圧Ｖoutの変化を示したものである。 FIG. 5E shows that the resistance value R2 of the second resistor 22 is three times the resistance value R1 of the first resistor 21 (R2 = 3 × R1), the resistance value Rt3≈0Ω of the resistor 43, and is smooth. The change of the voltage Vout between the terminals of the 3rd resistance 23 when the capacity | capacitance C1 of the capacitor | condenser 25 is 0pF is shown. FIG. 5F shows that the resistance value R2 of the second resistor 22 is three times the resistance value R1 of the first resistor 21 (R2 = 3 × R1), and the resistance value Rt3≈0Ω of the resistor 43. The change of the inter-terminal voltage Vout of the third resistor 23 when the capacitance C1 of the smoothing capacitor 25 is large is shown.
図５（ｅ）のコンデンサ２５の容量が０pFであるときは、正極導通状態であるときに、非接地回路１０の正側配線がトランジスタＱ11を介して接地電位部ＢＥに地絡し、第３の抵抗２３の端子間電圧Ｖoutが０Ｖとなる。一方、負極導通状態であるときに、非接地回路１０の負側配線がトランジスタＱ12を介して接地電位部ＢＥに地絡し、第３の抵抗２３の端子間電圧Ｖoutが、地絡が生じていない定常時の電圧（Ｖtyp＝Ｒ3／（Ｒ3＋４Ｒ1）≒Ｒ3／４Ｒ1）の４倍（４×Ｖtyp）となる。 When the capacitance of the capacitor 25 shown in FIG. 5 (e) is 0pF, when a positive electrode conductive state, the positive-side wiring ungrounded circuit 10 is grounded to the ground potential portion BE through the transistor Q 11, the 3, the voltage V out between the terminals of the resistor 23 becomes 0V. On the other hand, when it is negative conductive state, the negative side wiring ungrounded circuit 10 is grounded to the ground potential portion BE through the transistor Q 12, the terminal voltage V out of the third resistor 23, a ground fault It is four times (4 × V typ ) of the steady-state voltage (V typ = R3 / (R3 + 4R1) ≈R3 / 4R1) that has not occurred.
そして、平滑用コンデンサ２５の容量Ｃ1を増大させると、第３の抵抗２３の端子間電圧Ｖoutが定常時の電圧Ｖtypの２倍（２×Ｖtyp）となる。そのため、絶縁レベル検出手段３１は、第３の抵抗２３の端子間電圧Ｖoutが、定常時の電圧Ｖtypの２倍程度まで上昇したときに、３相地絡が生じたと判断することができる。 When the capacitance C1 of the smoothing capacitor 25 is increased, the inter-terminal voltage V out of the third resistor 23 becomes twice the steady-state voltage V typ (2 × V typ ). Therefore, the insulation level detection means 31 can determine that a three-phase ground fault has occurred when the inter-terminal voltage V out of the third resistor 23 has increased to about twice the steady-state voltage V typ. .
次に、図６（ａ）は、図１に示した非接地回路１０と接地電位部ＢＥ間の抵抗値（絶縁レベル）Ｒtと、第３の抵抗２３の端子間電圧Ｖoutの変化を示したものであり、縦軸がＶout（Ｖ）に設定され、横軸が絶縁レベルＲt（kΩ）に設定されている。 Next, FIG. 6A shows changes in the resistance value (insulation level) Rt between the non-ground circuit 10 and the ground potential portion BE shown in FIG. 1 and the voltage V out between the terminals of the third resistor 23. The vertical axis is set to V out (V), and the horizontal axis is set to the insulation level Rt (kΩ).
図６（ａ）において、ａ1は負側配線と接地電位部ＢＥ間の抵抗値が低下（負側地絡）したときの第３の抵抗２３の端子間電圧Ｖoutの変化を示している。また、ｂ1は正側配線と接地電位部ＢＥ間の抵抗値が低下したとき（正側地絡）の第３の抵抗２３の端子間電圧Ｖoutの変化を示している。また、ｃ1はインバータ１１とモータ４０との接続部と接地電位部ＢＥ間の抵抗値が低下したとき（３相地絡）の第３の抵抗２３の端子間電圧Ｖoutの変化を示している。 In FIG. 6A, a1 indicates a change in the voltage Vout between the terminals of the third resistor 23 when the resistance value between the negative side wiring and the ground potential portion BE decreases (negative side ground fault). Further, b1 represents a change in the voltage Vout between the terminals of the third resistor 23 when the resistance value between the positive wiring and the ground potential portion BE is lowered (positive ground fault). Further, c1 indicates a change in the voltage Vout between the terminals of the third resistor 23 when the resistance value between the connection portion of the inverter 11 and the motor 40 and the ground potential portion BE is lowered (three-phase ground fault). .
そして、絶縁レベル検出手段３１は、非接地回路１０と接地電位部ＢＥ間の抵抗値Ｒtが５００kΩ以上であるときは非接地回路１０と接地電位部ＢＥ間の地絡が生じていない（正常状態）にあると判定し、該抵抗値Ｒtが１５０kΩ以下となったときに地絡が生じていると判定する。 The insulation level detecting means 31 does not cause a ground fault between the non-ground circuit 10 and the ground potential portion BE when the resistance value Rt between the non-ground circuit 10 and the ground potential portion BE is 500 kΩ or more (normal state) ), And it is determined that a ground fault has occurred when the resistance value Rt is 150 kΩ or less.
そして、図６（ａ）においては、ａ1（負側地絡）とｃ1（３相地絡）では共にＲtが低下するに従ってＶoutが高くなっている。そのため、ａ1とｃ1については、ｃ1の３相地絡を基準として、非接地回路１０の短絡を判定する必要がある。しかし、このように３相短絡用の判定閾値Ｔhp1（≒２Ｖ）を基準として短絡を判定したときには、負側配線と接地電位部ＢＥ間の抵抗値が１０００kΩ以下になったときに、短絡が生じていると判定される。そのため、実際には非接地回路１０の短絡が生じていないにも拘わらず、非接地回路１０の短絡が生じていると判定されることになり、非接地回路１０の短絡を精度良く検出することができないという不都合がある。 In FIG. 6A, Vout increases as Rt decreases in both a1 (negative ground fault) and c1 (three-phase ground fault). Therefore, for a1 and c1, it is necessary to determine a short circuit of the non-grounded circuit 10 with reference to the three-phase ground fault of c1. However, when the short-circuit is determined based on the determination threshold Thp1 (≈2V) for the three-phase short circuit as described above, the short-circuit occurs when the resistance value between the negative wiring and the ground potential portion BE is 1000 kΩ or less. It is determined that Therefore, it is determined that the short circuit of the non-ground circuit 10 has occurred even though the short circuit of the non-ground circuit 10 has not actually occurred, and the short circuit of the non-ground circuit 10 is detected with high accuracy. There is an inconvenience that cannot be done.
そこで、図７を参照して、本実施の形態の非接地回路の絶縁性検出装置５０（以下、単に絶縁性検出装置５０という。本発明の非接地回路の絶縁性検出装置に相当する）は、上記不都合を解消して非接地回路１０の地絡を精度良く検出するための構成を備えている。以下、絶縁性検出装置５０について説明する。なお、上述した図１の非接地回路１０及び絶縁性検出装置２０と同様の構成については、同一の符号を付して説明を省略する。 Therefore, referring to FIG. 7, the non-grounded circuit insulation detection device 50 of the present embodiment (hereinafter simply referred to as insulation detection device 50. This corresponds to the non-grounded circuit insulation detection device of the present invention). The above-described inconvenience is eliminated, and the ground fault of the non-ground circuit 10 is accurately detected. Hereinafter, the insulation detection device 50 will be described. In addition, about the structure similar to the non-grounding circuit 10 and the insulation detection apparatus 20 of FIG. 1 mentioned above, the same code | symbol is attached | subjected and description is abbreviate | omitted.
絶縁性検出装置５０は、第１の抵抗２１と第３の抵抗２３との接続部Ｐ1（本発明の第１抵抗接続部、及び非接地抵抗接続部に相当する）に入力部が接続されたオペアンプ５２と、オペアンプ５２の出力部と接続された充放電設定回路６０と、充放電設定回路６０と接地電位部ＢＥとの間に接続されたコンデンサ５３と、コンデンサ５３の端子間電圧Ｖcを検出する電圧検出回路５４と、電圧検出回路５４と接続されて電圧検出信号が入力されるマイクロコンピュータ７０とを備えている。 The insulation detecting device 50 has an input portion connected to a connecting portion P1 (corresponding to the first resistance connecting portion and the non-grounded resistance connecting portion of the present invention) between the first resistor 21 and the third resistor 23. The operational amplifier 52, the charge / discharge setting circuit 60 connected to the output part of the operational amplifier 52, the capacitor 53 connected between the charge / discharge setting circuit 60 and the ground potential part BE, and the inter-terminal voltage Vc of the capacitor 53 are detected. And a microcomputer 70 that is connected to the voltage detection circuit 54 and receives a voltage detection signal.
オペアンプ５２はボルテージフォロワアンプを構成し、第３の抵抗２３の端子間電圧Ｖr3（Ｐ1と接地電位部ＢＥとの間の電圧）を充放電設定回路６０に出力する。充放電設定回路６０は、第４の抵抗６１及びダイオード６２からなる直列回路と、第５の抵抗６３とを並列に接続して構成されている。 The operational amplifier 52 constitutes a voltage follower amplifier, and outputs the voltage V r3 between the terminals of the third resistor 23 (voltage between P1 and the ground potential portion BE) to the charge / discharge setting circuit 60. The charge / discharge setting circuit 60 is configured by connecting a series circuit including a fourth resistor 61 and a diode 62 and a fifth resistor 63 in parallel.
ここで、非接地回路１０が３相地絡状態となると、トランジスタＱ11，Ｑ12，Ｑ21，Ｑ22，Ｑ31，Ｑ32をスイッチングしてインバータ１１からモータ４０に駆動電圧を出力するときに、上述したように正極導通状態（トランジスタＱ11がＯＮでトランジスタＱ12がＯＦＦ等）と、負極導通状態（トランジスタＱ12がＯＮでトランジスタＱ11がＯＦＦ等）とが交互に切り換わる。 Here, when the non-grounded circuit 10 is in a three-phase ground fault state, the transistors Q 11 , Q 12 , Q 21 , Q 22 , Q 31 , Q 32 are switched to output a drive voltage from the inverter 11 to the motor 40. In addition, as described above, the positive electrode conductive state (transistor Q 11 is ON and the transistor Q 12 is OFF, etc.) and the negative electrode conductive state (transistor Q 12 is ON and the transistor Q 11 is OFF, etc.) are alternately switched.
そして、負極導通状態においては、Ｐ1と接地電位部ＢＥ間の電圧がＶns（≒ＶM×Ｒ3／（Ｒ1＋Ｒ3））となり、第４の抵抗６１と第５の抵抗６３を経由して、Ｐ1からコンデンサ５３に向かって充電電流が流れる。一方、正極導通状態においては、Ｐ1と接地電位部ＢＥ間の電圧がＶps（≒０）となり、第５の抵抗６３を経由して、コンデンサ５３からＰ1に向かって放電電流が流れる。 In the negative conducting state, the voltage between P1 and the ground potential portion BE becomes V ns (≈VM × R3 / (R1 + R3)), and from P1 via the fourth resistor 61 and the fifth resistor 63 A charging current flows toward the capacitor 53. On the other hand, in the positive conducting state, the voltage between P1 and the ground potential portion BE becomes V ps (≈0), and a discharge current flows from the capacitor 53 toward P1 via the fifth resistor 63.
そして、充放電設定回路６０においては、負極導通状態におけるＰ1からコンデンサ５３への充電電流が、正極導通状態におけるコンデンサ５３からＰ1への放電電流よりも大きくなるように、第５の抵抗６３の抵抗値Ｒ5が第４の抵抗６１の抵抗値Ｒ4よりも高く設定されている。 In the charge / discharge setting circuit 60, the resistance of the fifth resistor 63 is set so that the charging current from P1 to the capacitor 53 in the negative conducting state is larger than the discharging current from the capacitor 53 to P1 in the positive conducting state. The value R5 is set higher than the resistance value R4 of the fourth resistor 61.
ここで、図８（ａ）は、充放電設定回路６０により、負極導通状態におけるＰ1からコンデンサ５３への充電電流が、正極導通状態におけるコンデンサ５３からＰ1への放電電流よりも大きくなるように設定したときの、第３の抵抗２３の端子間電圧Ｖr3と、コンデンサ５３の端子間電圧Ｖcの変化を、共通の時間軸（ｔ）により示したものである。 8A is set by the charge / discharge setting circuit 60 so that the charging current from P1 to the capacitor 53 in the negative conducting state is larger than the discharging current from the capacitor 53 to P1 in the positive conducting state. The change of the inter-terminal voltage V r3 of the third resistor 23 and the inter-terminal voltage V c of the capacitor 53 at this time is shown by a common time axis (t).
図８（ａ）においては、ｔ50〜ｔ51，ｔ52〜ｔ53，ｔ54〜ｔ55，ｔ56〜ｔ57，ｔ58〜ｔ59の各期間で負極導通状態となって、ＶoutがＶnsとなっている。また、ｔ51〜ｔ52，ｔ53〜ｔ54，ｔ55〜ｔ56，ｔ57〜ｔ58の各期間で正極導通状態となって、ＶoutがＶpsとなっている。 In FIG. 8 (a), a negative electrode conductive state in each period of t 50 ~t 51, t 52 ~t 53, t 54 ~t 55, t 56 ~t 57, t 58 ~t 59, V out Is V ns . In addition, the positive electrode is in a conductive state in each period of t 51 to t 52 , t 53 to t 54 , t 55 to t 56 , and t 57 to t 58 , and V out becomes V ps .
そして、負極導通状態では、Ｐ1からコンデンサ５３に充電電流が流れるため、Ｖcが上昇する。一方、正極導通状態では、コンデンサ５３からＰ１に放電電流が流れるため、Ｖcが低下する。そして、上述したように、充放電設定回路６０により、コンデンサ５３の充電電流が放電電流よりも大きくなるように設定されているため、ＶcがＶnsに向かって次第に上昇する。 In the negative electrode conducting state, charging current flows from P1 to the capacitor 53, so that Vc increases. On the other hand, in the positive conducting state, a discharge current flows from the capacitor 53 to P1, so that V c decreases. Then, as described above, the charge and discharge setting circuit 60, since the charging current of the capacitor 53 is set to be larger than the discharge current, V c is increased gradually toward the V ns.
そのため、絶縁レベル検出手段７１は、図６（ａ）を参照して、負側短絡の判定閾値Ｔhp2により３相地絡を検出することができる。そして、これにより、非接地回路１０の地絡検出の精度を向上させることができる。 Therefore, the insulation level detection means 71 can detect a three-phase ground fault with the negative side short-circuit determination threshold Thp2 with reference to FIG. And thereby, the precision of the ground fault detection of the non-grounding circuit 10 can be improved.
また、図７に示した構成では、充放電設定回路６０により、負極導通状態におけるＰ1からコンデンサ５３への充電電流が、正極導通状態におけるコンデンサ５３からＰ1への放電電流よりも大きくなるように構成したが、逆に、正極導通状態におけるコンデンサ５３からＰ1への放電電流が、負極導通状態におけるＰ1からコンデンサ５３への充電電流よりも大きくなるように構成してもよい。 In the configuration shown in FIG. 7, the charging / discharging setting circuit 60 is configured so that the charging current from P1 to the capacitor 53 in the negative conducting state is larger than the discharging current from the capacitor 53 to P1 in the positive conducting state. However, conversely, the discharge current from the capacitor 53 to P1 in the positive electrode conducting state may be configured to be larger than the charging current from P1 to the capacitor 53 in the negative electrode conducting state.
この場合には、図７のダイオード６２の向きを逆（アノードを第４の抵抗６１に接続し、カソードをオペアンプ５２に接続する）にし、第５の抵抗６３の抵抗値Ｒ5を第４の抵抗６１の抵抗値Ｒ4よりも大きくして、正極導通状態におけるコンデンサ５３からＰ1への放電電流が、負極導通状態におけるＰ1からコンデンサ５３への充電電流よりも大きくなるように設定する。 In this case, the direction of the diode 62 in FIG. 7 is reversed (the anode is connected to the fourth resistor 61 and the cathode is connected to the operational amplifier 52), and the resistance value R5 of the fifth resistor 63 is set to the fourth resistor. The discharge current from the capacitor 53 to P1 in the positive conducting state is set to be larger than the charging current from P1 to the capacitor 53 in the negative conducting state.
図８（ｂ）は、このように、正極導通状態におけるコンデンサ５３からＰ1への放電電流が、負極導通状態におけるＰ1からコンデンサ５３への充電電流よりも大きくなるように設定したときの、第３の抵抗２３の端子間電圧Ｖoutと、コンデンサ５３の端子間電圧Ｖcを、図８（ａ）と同様に、共通の時間軸（ｔ）により示したものである。 FIG. 8B shows a third example when the discharge current from the capacitor 53 to P1 in the positive electrode conducting state is set to be larger than the charging current from P1 to the capacitor 53 in the negative electrode conducting state. The terminal voltage Vout of the resistor 23 and the terminal voltage Vc of the capacitor 53 are shown by a common time axis (t) as in FIG. 8A.
図８（ｂ）においては、ｔ60〜ｔ61，ｔ62〜ｔ63，ｔ64〜ｔ65，ｔ66〜ｔ67，ｔ68〜ｔ69の各期間で負極導通状態となって、Ｖr3がＶnsとなっている。また、ｔ61〜ｔ62，ｔ63〜ｔ64，ｔ65〜ｔ66，ｔ67〜ｔ68の各期間で正極導通状態となって、Ｖr3がＶpsとなっている。 In FIG. 8B, the negative electrode conductive state is established in each period of t 60 to t 61 , t 62 to t 63 , t 64 to t 65 , t 66 to t 67 , t 68 to t 69 , and V r3 Is V ns . Further, the positive electrode conduction state is obtained in each period of t 61 to t 62 , t 63 to t 64 , t 65 to t 66 , t 67 to t 68 , and V r3 is V ps .
そして、負極導通状態では、Ｐ1からコンデンサ５３に充電電流が流れるため、Ｖcが上昇する。一方、正極導通状態では、コンデンサ５３からＰ１に放電電流が流れるため、Ｖcが低下する。そして、上述したように、充放電設定回路により、コンデンサ５３の放電電流が充電電流よりも大きくなるように設定されているため、ＶcがＶ ps に向かって次第に下降する。 In the negative electrode conducting state, charging current flows from P1 to the capacitor 53, so that Vc increases. On the other hand, in the positive conducting state, a discharge current flows from the capacitor 53 to P1, so that V c decreases. As described above, since the discharging current of the capacitor 53 is set to be larger than the charging current by the charging / discharging setting circuit, V c gradually decreases toward V ps .
そのため、絶縁レベル検出手段７１は、図６（ａ）を参照して、正側短絡の判定閾値Ｔhn1により３相地絡を検出することができる。そして、これにより、非接地回路１０の地絡検出の精度を向上させることができる。 Therefore, the insulation level detection means 71 can detect a three-phase ground fault by the positive side short-circuit determination threshold Thn1 with reference to FIG. And thereby, the precision of the ground fault detection of the non-grounding circuit 10 can be improved.
また、図７を参照して、第３の抵抗２３と並列にツェナーダイオード５１を接続することにより、オペアンプ５２に許容範囲（ＢＥ〜Ｖcc）を超えた電圧が入力されることを防止しつつ、非接地回路１０の地絡の検出精度を向上させることができる。 Further, referring to FIG. 7, by connecting a Zener diode 51 in parallel with the third resistor 23, it is possible to prevent a voltage exceeding the allowable range (BE to V cc ) from being input to the operational amplifier 52. The ground fault detection accuracy of the non-ground circuit 10 can be improved.
図６（ｂ）は、ツェナーダイオード５１を接続したことによる効果を示した説明図であり、図６（ａ）と同様に、縦軸が第３の抵抗２３の端子間電圧Ｖoutに設定され、横軸が非接地回路１０と接地電位部ＢＥ間の抵抗Ｒtに設定されている。図６（ｂ）において、ａ2は負側配線と接地電位部ＢＥ間の絶縁レベルが低下（負側地絡）したときの第３の抵抗２３の端子間電圧Ｖoutの変化を示している。また、ｂ2は正側配線と接地電位部ＢＥ間の絶縁レベルが低下したとき（正側地絡）の第３の抵抗２３の端子間電圧Ｖoutの変化を示している。 FIG. 6B is an explanatory diagram showing the effect obtained by connecting the Zener diode 51. As in FIG. 6A, the vertical axis is set to the inter-terminal voltage V out of the third resistor 23. The horizontal axis is set to the resistance Rt between the non-ground circuit 10 and the ground potential portion BE. In FIG. 6B, a2 shows a change in the voltage Vout between the terminals of the third resistor 23 when the insulation level between the negative side wiring and the ground potential portion BE is lowered (negative side ground fault). Further, b2 shows a change in the voltage Vout between the terminals of the third resistor 23 when the insulation level between the positive side wiring and the ground potential portion BE is lowered (positive side ground fault).
図６（ｂ）のａ2では、ツェナーダイオード５１により、正側配線と接地電位部ＢＥ間の抵抗Ｒtが低下して正側地絡の判定閾値（１５０kΩ）以下になったときの第３の抵抗２３の端子間電圧Ｖoutが、ツェナーダイオード５１がない場合のｄからＶcc（≒５Ｖ）に抑えられている。そのため、Ｒtが地絡判定閾値付近にある１５０kΩ〜５００kΩの範囲でのａ2の傾きを大きくして、非絶縁回路１０の地絡検出の精度を高めることができる。 In a2 of FIG. 6B, the third resistance when the resistance Rt between the positive-side wiring and the ground potential portion BE is lowered by the Zener diode 51 and becomes equal to or less than the determination threshold (150 kΩ) of the positive-side ground fault. The voltage V out between the terminals 23 is suppressed from d to V cc (≈5 V) when the Zener diode 51 is not provided. Therefore, the slope of a2 in the range of 150 kΩ to 500 kΩ where Rt is near the ground fault determination threshold value can be increased, and the accuracy of ground fault detection of the non-insulated circuit 10 can be improved.
次に、図９を参照して、絶縁性検出装置５０による正側地絡と負側地絡の検出について説明する。負側配線と接地電位部ＢＥ間の抵抗Ｒt2が低くなると、上述した式（４）により、第３の抵抗２３の端子間電圧Ｖoutが上昇する。そして、充放電設定回路６０を介してコンデンサ５３に充電電流が流れ、コンデンサ５３の端子間電圧ＶcがＶoutの上昇分だけ上昇する。そのため、絶縁レベル検出手段７１は、Ｖcが正側地絡の判定閾値以上となったときに、非接地回路１０と接地電位部ＢＥ間の地絡が生じていると判定することができる。 Next, with reference to FIG. 9, the detection of the positive side ground fault and the negative side ground fault by the insulation detection apparatus 50 is demonstrated. When the resistance Rt2 between the negative side wiring and the ground potential portion BE is lowered, the voltage Vout between the terminals of the third resistor 23 is increased by the above-described equation (4). Then, the charge and discharge setting circuit 60 to the charging current flows into the capacitor 53 through the inter-terminal voltage V c of the capacitor 53 increases by increase in the V out. Therefore, the insulation level detection means 71 can determine that a ground fault has occurred between the non-ground circuit 10 and the ground potential portion BE when V c becomes equal to or greater than the positive-side ground fault determination threshold.
また、正側配線と接地電位部ＢＥ間の抵抗Ｒt1が低くなると、上述した式（４）に示したように、第３の抵抗２３の端子間電圧Ｖoutが低下する。そして、コンデンサ５３に充電されていた電荷が、充放電設定回路６０を介して放電され、コンデンサ５３の端子間電圧ＶcがＶoutの低下分だけ低下する。そのため、絶縁レベル検出手段７１は、Ｖcが負側地絡の判定閾値以下となったときに、非接地回路１０と接地電位部ＢＥ間の地絡が生じていると判定することができる。 Further, when the resistance Rt1 between the positive-side wiring and the ground potential portion BE becomes low, the inter-terminal voltage Vout of the third resistor 23 decreases as shown in the above-described equation (4). Then, electric charge stored in the capacitor 53 is discharged through the discharge setting circuit 60, the inter-terminal voltage V c of the capacitor 53 is lowered by lowering content of V out. Therefore, the insulation level detecting means 71 can determine that a ground fault has occurred between the non-ground circuit 10 and the ground potential portion BE when V c becomes equal to or less than the negative ground fault determination threshold.
なお、本発明の充放電設定回路の構成は、図７に示した充放電回路６０に限るものではなく、３相地絡が生じたときの負極導通状態におけるコンデンサ５３への充電電流の大きさと、正側導通状態におけるコンデンサ５３からの放電電流の大きさと異なるレベルに設定するものであればよく、例えば、図１０示した充放電設定回路８０を用いてもよい。 The configuration of the charging / discharging setting circuit of the present invention is not limited to the charging / discharging circuit 60 shown in FIG. 7, and the magnitude of the charging current to the capacitor 53 in the negative electrode conducting state when a three-phase ground fault occurs. As long as it is set to a level different from the magnitude of the discharge current from the capacitor 53 in the positive conduction state, for example, the charge / discharge setting circuit 80 shown in FIG. 10 may be used.
図１０に示した絶縁性検出装置９０は、図７に示した絶縁性検出装置５０の充放電設定回路６０を充放電設定回路９０に置き換えたものである。充放電設定回路９０は、第２のダイオード９３及び第６の抵抗９２からなる直列回路を、コンデンサ５３と並列に接続し、第１の抵抗２１及び第３の抵抗２３の接続箇所Ｐ1とコンデンサ５３との間に第１のダイオード９１を接続して構成されている。 The insulation detection device 90 shown in FIG. 10 is obtained by replacing the charge / discharge setting circuit 60 of the insulation detection device 50 shown in FIG. The charge / discharge setting circuit 90 connects a series circuit including a second diode 93 and a sixth resistor 92 in parallel with the capacitor 53, and connects the connection point P 1 between the first resistor 21 and the third resistor 23 and the capacitor 53. The first diode 91 is connected between the two.
この場合、第１のダイオード９１は、Ｐ1からコンデンサ５３への向きを順方向として接続されており、第２のダイオード９３は、コンデンサ５３と第１のダイオード９１との接続部から接地電位部ＢＥへの向きを順方向として接続されている。また、コンデンサ５３と並列にツェナーダイオード８５が接続されている。ツェナーダイオード８５は、アノードが接地電位部ＢＥに接続されると共に、カソードが第１のダイオード９１とコンデンサ５３の接続部に接続されており、電圧検出回路５４に許容範囲（ＢＥ〜Ｖcc）を越えた電圧が入力されることを防止している。また、ツェナーダイオード８５を設けることにより、上述した図９の絶縁性検出装置５０と同様に、非接地回路１０の地絡の検出精度を向上させることができる。 In this case, the first diode 91 is connected with the direction from P1 to the capacitor 53 as the forward direction, and the second diode 93 is connected to the ground potential portion BE from the connection portion between the capacitor 53 and the first diode 91. Connected as the forward direction. A zener diode 85 is connected in parallel with the capacitor 53. The Zener diode 85 has an anode connected to the ground potential portion BE and a cathode connected to the connection portion of the first diode 91 and the capacitor 53, and allows the voltage detection circuit 54 to provide an allowable range (BE to V cc ). It prevents the voltage exceeding the input. Further, by providing the Zener diode 85, the ground fault detection accuracy of the non-grounded circuit 10 can be improved in the same manner as the insulating detection device 50 of FIG. 9 described above.
充放電設定回路９０においては、３相地絡が生じたときの負極導通状態では、Ｐ1からダイオード９１を介してコンデンサ５３に充電電流が流れ、この充電電流の大きさは第１の抵抗２１及び第３の抵抗２３の抵抗値により変化する。また、３相地絡が生じたときの正極導通状態では、コンデンサ５３から第２のダイオード９３及び第６の抵抗９２を介して放電電流が流れる。そのため、第１の抵抗２１及び第３の抵抗２３と第６の抵抗９２の抵抗値の設定により、負極導通状態におけるＰ1からコンデンサ５３への充電電流と、正極導通状態におけるコンデンサ５３からＰ1への放電電流を、異なるレベルに設定することができる。 In the charge / discharge setting circuit 90, in the negative conduction state when a three-phase ground fault occurs, a charging current flows from P1 to the capacitor 53 via the diode 91, and the magnitude of this charging current is the first resistor 21 and It changes depending on the resistance value of the third resistor 23. Further, in the positive electrode conduction state when the three-phase ground fault occurs, a discharge current flows from the capacitor 53 via the second diode 93 and the sixth resistor 92. Therefore, by setting the resistance values of the first resistor 21, the third resistor 23, and the sixth resistor 92, the charging current from the P1 to the capacitor 53 in the negative conducting state and the current from the capacitor 53 to the P1 in the positive conducting state are set. The discharge current can be set to different levels.
なお、図７に示した絶縁性検出装置５０においては、ツェナーダイオード５１を備えたが、第１の抵抗２１と第２の抵抗２２と第３の抵抗２３とを、第３の抵抗２３の端子間電圧ＶoutがＶccを超えないように設定する場合には、ツェナーダイオード５１を備える必要はない。 7 includes the Zener diode 51, the first resistor 21, the second resistor 22, and the third resistor 23 are connected to the terminal of the third resistor 23. When setting so that the inter-voltage V out does not exceed V cc , it is not necessary to provide the Zener diode 51.
また、図１０に示した絶縁性検出装置８０においては、ツェナーダイオード８５を備えたが、第１の抵抗２１と第２の抵抗２２と第３の抵抗２３とを、第３の抵抗２３の端子間電圧がＶccと第１のダイオード９１の順方向電圧との合計電圧を超えないように設定する場合には、ツェナーダイオード８５を備える必要はない。 10 includes the Zener diode 85. However, the first resistor 21, the second resistor 22, and the third resistor 23 are connected to the terminal of the third resistor 23. If the interphase voltage is set so as not to exceed the total voltage of the forward voltage of V cc and the first diode 91 need not comprise a Zener diode 85.
また、本実施の形態では、図７に示したように、第２の抵抗２２と第３の抵抗２３との接続部を接地電位部ＢＥに接続したが、第１の抵抗２１と第３の抵抗２３との接続部を車両の接地電位部ＢＥに接続し、第３の抵抗２３の端子間電圧に基いて、非接地回路１０と接地電位部ＢＥ間の絶縁レベルを検出するようにしてもよい。 Further, in the present embodiment, as shown in FIG. 7, the connection portion between the second resistor 22 and the third resistor 23 is connected to the ground potential portion BE, but the first resistor 21 and the third resistor 23 are connected to the ground potential portion BE. The connection portion with the resistor 23 is connected to the ground potential portion BE of the vehicle, and the insulation level between the non-ground circuit 10 and the ground potential portion BE is detected based on the voltage between the terminals of the third resistor 23. Good.
また、本実施の形態では、車両の接地電位部から絶縁して車両に搭載された非接地回路１０と、接地電位部との絶縁レベルを検出する絶縁性検出装置を示したが、非接地回路は車両に搭載されるものには限られず、接地電位部から絶縁して配置される非接地回路であれば、本発明の適用が可能である。 In the present embodiment, the non-grounding circuit 10 that is insulated from the ground potential portion of the vehicle and mounted on the vehicle and the insulation detection device that detects the insulation level between the ground potential portion are shown. Is not limited to the one mounted on the vehicle, and the present invention can be applied to any non-grounded circuit that is insulated from the ground potential portion.
また、本実施の形態では、本発明のインバータと接続される電気負荷として電気モータ４０を示したが、スイッチング素子によるスイッチングによりインバータから供給される電力により作動する電気負荷であればよい。 In the present embodiment, the electric motor 40 is shown as an electric load connected to the inverter of the present invention.
１０…非接地回路、１１…インバータ、１２…直流電源、２０…絶縁性検出装置、２１…第１の抵抗、２２…第２の抵抗、２３…第３の抵抗、２５…平滑用コンデンサ、２６…オペアンプ、３０…マイクロコンピュータ、３１…絶縁レベル検出手段、４０…モータ（電気負荷）、５０…（本発明の）絶縁性検出装置、５１…ツェナーダイオード、５２…オペアンプ、６０…充放電設定回路、５３…コンデンサ、５４…電圧検出回路、７０…マイクロコンピュータ、７１…絶縁性検出手段、Ｑ11，Ｑ12，Ｑ21，Ｑ22，Ｑ31，Ｑ32…トランジスタ（スイッチング素子）、８０…（本発明の）絶縁性検出装置、９０…充放電設定回路 DESCRIPTION OF SYMBOLS 10 ... Non-grounding circuit, 11 ... Inverter, 12 ... DC power supply, 20 ... Insulating detection device, 21 ... First resistor, 22 ... Second resistor, 23 ... Third resistor, 25 ... Smoothing capacitor, 26 DESCRIPTION OF SYMBOLS ... Operational amplifier, 30 ... Microcomputer, 31 ... Insulation level detection means, 40 ... Motor (electric load), 50 ... (Insulation detection device), 51 ... Zener diode, 52 ... Operational amplifier, 60 ... Charge / discharge setting circuit , 53 ... capacitor, 54 ... voltage detection circuit, 70 ... microcomputer, 71 ... insulation detection means, Q 11 , Q 12 , Q 21 , Q 22 , Q 31 , Q 32 ... transistor (switching element), 80 ... ( Insulating detector of the present invention, 90 ... charge / discharge setting circuit
Claims (7)
一端が前記正側配線に接続されて、前記非接地回路と前記接地電位部間の絶縁性を維持するための絶縁基準値よりも高い抵抗を有する第１の抵抗と、
一端が前記負側配線に接続されて、前記絶縁基準値よりも高い抵抗を有する第２の抵抗と、
前記第１の抵抗の他端と前記第２の抵抗の他端間に接続された第３の抵抗と、
前記第１の抵抗と前記第３の抵抗との接続部である第１抵抗接続部と、前記第２の抵抗と前記第３の抵抗との接続部である第２抵抗接続部とのうちのいずれか一方を、前記接地電位部に接続する接地配線と、
一端が前記接地電位部と接続されたコンデンサと、
該コンデンサの他端と、前記第１抵抗接続部と前記第２抵抗接続部とのうちの前記接地配線と接続されていない方の接続部である非接地抵抗接続部との間に接続されて、該非接地抵抗接続部から該コンデンサへの充電電流と、該コンデンサから該非接地接続部への放電電流とを異なるレベルに設定する充放電設定回路と、
前記インバータのスイッチング素子により、前記正極導通状態と前記負極導通状態とが切替えられているときに、前記コンデンサの端子間電圧に基づいて、前記非接地回路と前記接地電位部との間の絶縁レベルを検出する絶縁レベル検出手段とを備えたことを特徴とする非接地回路の絶縁性検出装置。 Connected between the DC power supply, the positive wiring connected to the positive electrode of the DC power supply, the negative wiring connected to the negative electrode of the DC power supply, and the positive wiring and the negative wiring to the electrical load. An inverter having a switching element for switching between a positive conducting state in which the positive side wiring is conducted to the connection point with the electric load and a negative conducting state in which the negative side wiring is conducted to the connection point to the electric load. An insulation detection device for a non-ground circuit for detecting an insulation level between the non-ground circuit arranged insulated from the ground potential part and the ground potential part,
A first resistor having one end connected to the positive wiring and having a resistance higher than an insulation reference value for maintaining insulation between the non-grounded circuit and the ground potential portion;
A second resistor having one end connected to the negative wiring and having a resistance higher than the insulation reference value;
A third resistor connected between the other end of the first resistor and the other end of the second resistor;
Of the first resistance connection portion that is a connection portion between the first resistor and the third resistor, and the second resistance connection portion that is a connection portion between the second resistor and the third resistor. Either one of the ground wiring connecting to the ground potential portion,
A capacitor having one end connected to the ground potential portion;
The capacitor is connected between the other end of the capacitor and a non-ground resistance connection portion which is a connection portion of the first resistance connection portion and the second resistance connection portion which is not connected to the ground wiring. A charge / discharge setting circuit for setting a charging current from the non-grounded resistor connection to the capacitor and a discharge current from the capacitor to the non-grounded connection at different levels;
An insulation level between the non-grounded circuit and the ground potential portion based on a voltage between terminals of the capacitor when the positive electrode conducting state and the negative electrode conducting state are switched by the switching element of the inverter. An insulation detection device for a non-ground circuit, comprising: an insulation level detection means for detecting
第４の抵抗とダイオードとを直列に接続して構成され、前記第５の抵抗と並列に接続された直列回路とを備えたことを特徴とする請求項１記載の非接地回路の絶縁性検出装置。 The charge / discharge setting circuit includes a fifth resistor connected between the capacitor and the non-grounded resistance connection portion,
2. The insulation detection of a non-grounded circuit according to claim 1, further comprising a series circuit configured by connecting a fourth resistor and a diode in series, and connected in parallel with the fifth resistor. apparatus.
前記コンデンサの前記非接地抵抗接続部側の端子と前記非接地抵抗接続部との間に、前記非接地抵抗接続部から前記コンデンサへの向きを順方向として接続された第１のダイオードと、
第６の抵抗と第２のダイオードとを直列に接続して構成され、該第２のダイオードの順方向を前記非接地抵抗接続部から前記接地電位部への向きとして、前記コンデンサと並列に接続された直列回路とを備えたことを特徴とする請求項１記載の非接地回路の絶縁性検出装置。 The charge / discharge setting circuit includes:
A first diode connected between a terminal of the capacitor on the non-ground resistance connection portion side and the non-ground resistance connection portion with a direction from the non-ground resistance connection portion to the capacitor as a forward direction;
A sixth resistor and a second diode are connected in series, and the forward direction of the second diode is connected in parallel with the capacitor with the direction from the non-ground resistance connection portion to the ground potential portion. The insulation detection device for a non-grounded circuit according to claim 1, further comprising: a series circuit configured as described above.
前記絶縁レベル検出手段は、前記コンデンサの端子間電圧が、第１の所定電圧以上になったときに、前記負側配線と前記接地電位部間、又は前記インバータと電気負荷との接続部と前記接地電位部間が短絡状態にあると判断することを特徴とする請求項１から請求項５のうちいずれか１項記載の非接地回路の絶縁性検出装置。 The charging / discharging setting circuit sets a charging current from the non-ground resistance connection portion to the capacitor to be larger than a discharging current from the capacitor to the non-ground resistance connection portion,
When the voltage between the terminals of the capacitor becomes equal to or higher than a first predetermined voltage, the insulation level detection means is connected between the negative wiring and the ground potential part, or a connection part between the inverter and the electric load, and the 6. The insulation detecting device for a non-grounded circuit according to claim 1, wherein it is determined that a ground potential portion is in a short-circuited state.
前記絶縁レベル検出手段は、前記コンデンサの端子間電圧が、第２の所定電圧以下になったときに、前記正側配線と前記接地電位部間、又は前記インバータと電気負荷との接続部と前記接地電位部間が短絡状態にあると判断することを特徴とする請求項１から請求項５のうちいずれか１項記載の非接地回路の絶縁性検出装置。 The charge / discharge setting circuit sets a discharge current from the capacitor to the non-grounded resistance connection portion to be larger than a charge current from the non-grounded resistance connection portion to the capacitor,
When the voltage between the terminals of the capacitor becomes equal to or lower than a second predetermined voltage, the insulation level detecting means is connected between the positive wiring and the ground potential portion, or a connection portion between the inverter and an electric load, and the 6. The insulation detecting device for a non-grounded circuit according to claim 1, wherein it is determined that a ground potential portion is in a short-circuited state.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2008207345A JP4804514B2 (en) | 2008-08-11 | 2008-08-11 | Non-grounded circuit insulation detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2008207345A JP4804514B2 (en) | 2008-08-11 | 2008-08-11 | Non-grounded circuit insulation detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2010043916A JP2010043916A (en) | 2010-02-25 |
| JP4804514B2 true JP4804514B2 (en) | 2011-11-02 |
Family
ID=42015414
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2008207345A Expired - Fee Related JP4804514B2 (en) | 2008-08-11 | 2008-08-11 | Non-grounded circuit insulation detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4804514B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111352005A (en) * | 2020-02-28 | 2020-06-30 | 江西五十铃汽车有限公司 | Efficient processing method for insulation alarm fault problem of electric vehicle |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8618809B2 (en) * | 2010-06-15 | 2013-12-31 | Deere & Company | Electrical isolation detection with enhanced dynamic range |
| JP5414777B2 (en) * | 2011-12-22 | 2014-02-12 | 株式会社正興電機製作所 | DC circuit ground fault detection apparatus and method |
| DE102018221479A1 (en) * | 2018-12-12 | 2020-06-18 | Robert Bosch Gmbh | Circuit arrangement for fault detection in an unearthed high-voltage system |
| JP7445894B2 (en) | 2020-12-28 | 2024-03-08 | Ａｎｐ株式会社 | Earth leakage detection device |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6856137B2 (en) * | 2002-02-19 | 2005-02-15 | Bae Systems Controls Inc. | Ground fault detection system and method |
| JP2004289903A (en) * | 2003-03-20 | 2004-10-14 | Toyota Motor Corp | Inverter device |
-
2008
- 2008-08-11 JP JP2008207345A patent/JP4804514B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111352005A (en) * | 2020-02-28 | 2020-06-30 | 江西五十铃汽车有限公司 | Efficient processing method for insulation alarm fault problem of electric vehicle |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2010043916A (en) | 2010-02-25 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6992490B2 (en) | Ground fault detection device | |
| US9255957B2 (en) | Earth fault detection circuit and power source device | |
| JP5113741B2 (en) | Battery pack and disconnection detection method thereof | |
| US10222423B2 (en) | Electrical storage system | |
| US9709631B2 (en) | Diagnosis apparatus for field winding type rotating electric machine and diagnosis method for field winding type rotating electric machine | |
| US8929113B2 (en) | Capacitor discharger for power conversion system | |
| WO2013190733A1 (en) | Leak detection device | |
| US11329474B2 (en) | Switching controller with adaptive overheating protection | |
| US9825555B2 (en) | Semiconductor control device, switching device, inverter, and control system | |
| JP4978970B2 (en) | Non-grounded circuit insulation detector | |
| JP4804514B2 (en) | Non-grounded circuit insulation detector | |
| JP6710621B2 (en) | Ground fault detection circuit Reverse voltage protection circuit | |
| CN103023010A (en) | Control unit for automobile | |
| US10744963B2 (en) | Charge/discharge device | |
| CN113841059A (en) | Electric leakage detection device and power supply system for vehicle | |
| WO2021106285A1 (en) | Earth leakage detecting device, and vehicular power supply system | |
| JP2010035284A (en) | Overcurrent protection circuit | |
| US11843096B2 (en) | Internal resistance detection device and power source device | |
| JP6836411B2 (en) | Ground fault detector, power supply system | |
| JP5202119B2 (en) | Multi-output judgment circuit | |
| JP4123441B2 (en) | Inrush current limiting power switch circuit for vehicles | |
| JP6955951B2 (en) | Discharge device | |
| JP4983527B2 (en) | Leakage detection method | |
| JP5195518B2 (en) | Short-circuit detection device | |
| WO2024116752A1 (en) | On-vehicle power supply device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20110427 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20110510 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20110630 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20110719 |
|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20110809 |
|
| R150 | Certificate of patent or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20140819 Year of fee payment: 3 |
|
| LAPS | Cancellation because of no payment of annual fees |