JP6229584B2 - Ground fault judgment device - Google Patents

Ground fault judgment device Download PDF

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JP6229584B2
JP6229584B2 JP2014089642A JP2014089642A JP6229584B2 JP 6229584 B2 JP6229584 B2 JP 6229584B2 JP 2014089642 A JP2014089642 A JP 2014089642A JP 2014089642 A JP2014089642 A JP 2014089642A JP 6229584 B2 JP6229584 B2 JP 6229584B2
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ground fault
peak value
fault determination
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隼 溝口
隼 溝口
雅也 伊藤
雅也 伊藤
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Denso Corp
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Description

本発明は、地絡の有無を検出する地絡判定装置に関する。   The present invention relates to a ground fault determination device that detects the presence or absence of a ground fault.

例えばハイブリッド自動車や電気自動車などの高電圧のバッテリ系(高電圧回路)を備える車両では、高電圧回路と車両との間に対地絶縁抵抗が存在している。この対地絶縁抵抗が地絡により低下すると漏電が生じるおそれがある。そこで漏電から乗員等を保護するために、地絡の有無を判定する地絡判定装置が設けられている。   For example, in a vehicle including a high voltage battery system (high voltage circuit) such as a hybrid vehicle or an electric vehicle, a ground insulation resistance exists between the high voltage circuit and the vehicle. If this ground insulation resistance is lowered due to a ground fault, there is a risk of leakage. Therefore, in order to protect passengers and the like from electric leakage, a ground fault determination device that determines the presence or absence of a ground fault is provided.

例えば特許文献1において、地絡判定装置は、カップリングコンデンサを介して地絡判定装置と高電圧部とが直流的に絶縁された状態で、高電圧部に対して抵抗を介して所定周波数の交流信号(パルス信号)を印加する。そして、抵抗と対地絶縁抵抗との分圧で決定される交流信号の波高値(波高値)の変動から、対地絶縁抵抗の低下に伴う地絡の有無を判定している。   For example, in Patent Document 1, the ground fault determination device has a predetermined frequency via a resistor with respect to the high voltage portion in a state where the ground fault determination device and the high voltage portion are galvanically insulated via a coupling capacitor. An AC signal (pulse signal) is applied. And the presence or absence of the ground fault accompanying the fall of ground insulation resistance is determined from the fluctuation | variation of the peak value (peak value) of the alternating current signal determined by the partial pressure of resistance and ground insulation resistance.

特開2003−274504号公報JP 2003-274504 A

しかし従来の地絡判定では、車両の製造時などに決定された地絡判定値を用いて地絡判定が実施されている。しかしバッテリ個体差や経年劣化などに伴う対地絶縁抵抗のばらつきや、地絡判定装置が有する各素子の個体差や劣化によるばらつきがあるため、このことが地絡判定の精度に影響してしまう。   However, in the conventional ground fault determination, the ground fault determination is performed using the ground fault determination value determined at the time of manufacturing the vehicle. However, since there are variations in ground insulation resistance due to individual battery differences and aging degradation, and variations due to individual differences and deterioration of each element of the ground fault determination device, this affects the accuracy of ground fault determination.

本発明は、上記実情を鑑み、地絡判定装置による地絡判定の精度を高めることを技術課題とする。   In view of the above circumstances, an object of the present invention is to improve the accuracy of ground fault determination by a ground fault determination device.

本発明では、高電圧部の対地絶縁抵抗に印加される所定の発振周波数の交流信号を出力する交流信号出力手段と、交流信号出力手段と対地絶縁抵抗との間に設けられたカップリングコンデンサと、交流信号出力手段とカップリングコンデンサとの間で交流信号を取り込み、当該交流信号の波高値を算出する波高値算出手段と、波高値算出手段により算出した波高値と所定の地絡判定値との比較により高電圧部の地絡判定を実施する地絡判定手段と、所定条件の成立に応じて、波高値算出手段により算出した時系列の波高値を用いて、地絡判定値を設定する判定値設定手段と、を備えることを特徴とする地絡判定装置。   In the present invention, AC signal output means for outputting an AC signal having a predetermined oscillation frequency applied to the ground insulation resistance of the high voltage portion, a coupling capacitor provided between the AC signal output means and the ground insulation resistance, A peak value calculating means for taking in an AC signal between the AC signal output means and the coupling capacitor and calculating a peak value of the AC signal, a peak value calculated by the peak value calculating means, and a predetermined ground fault judgment value The ground fault determination means for performing the ground fault determination of the high voltage part by comparing the above and the time series peak value calculated by the peak value calculation means according to the establishment of the predetermined condition, the ground fault determination value is set. A ground fault determination device comprising: a determination value setting unit.

上記発明において、地絡判定装置で検出した交流信号の波高値を用いて地絡判定値を設定する。この場合、高電圧部や地絡判定装置の個体差や経年劣化などに起因する地絡判定の誤差を抑えることができ、地絡判定の精度を高めることができる。   In the said invention, a ground fault determination value is set using the peak value of the alternating current signal detected with the ground fault determination apparatus. In this case, it is possible to suppress ground fault determination errors caused by individual differences in the high voltage section and the ground fault determination device, aging degradation, and the like, and the accuracy of ground fault determination can be increased.

本実施形態に係る地絡判定装置の回路図。The circuit diagram of the ground fault determination apparatus concerning this embodiment. 地絡判定値の学習処理の説明図。Explanatory drawing of the learning process of a ground fault determination value. 地絡判定パラメータの補正処理の説明図。Explanatory drawing of the correction process of a ground fault determination parameter. 地絡判定パラメータの補正処理の説明図。Explanatory drawing of the correction process of a ground fault determination parameter. 低周波ノイズ重畳時における無効化処理の説明図。Explanatory drawing of the invalidation process at the time of low frequency noise superimposition. 地絡判定処理のフローチャート。The flowchart of a ground fault determination process. 地絡判定処理のタイミングチャート。The timing chart of a ground fault determination process.

以下、本発明の実施形態を図面に基づいて説明する。図1に示す地絡判定装置は、ハイブリッド車両や電気自動車等の車両に搭載された高電圧バッテリ(以下、バッテリと記す)の地絡(漏電)を判定する装置である。本実施形態では、バッテリ11、電気負荷10、SMR15を含む回路を高電圧回路1と称する。   Hereinafter, embodiments of the present invention will be described with reference to the drawings. The ground fault determination device shown in FIG. 1 is a device that determines a ground fault (leakage) of a high voltage battery (hereinafter referred to as a battery) mounted on a vehicle such as a hybrid vehicle or an electric vehicle. In the present embodiment, a circuit including the battery 11, the electric load 10, and the SMR 15 is referred to as a high voltage circuit 1.

バッテリ11は、車両の電気負荷10に電力を供給する電源であり、例えば、複数個のリチウムイオン電池等が直列に接続された電池群として構成されている。バッテリ11と、電気負荷10とはシステムメインリレー(system main relay、以下SMR15と記す)を介して接続されている。   The battery 11 is a power source that supplies electric power to the electric load 10 of the vehicle, and is configured as a battery group in which a plurality of lithium ion batteries or the like are connected in series, for example. The battery 11 and the electrical load 10 are connected via a system main relay (hereinafter referred to as SMR 15).

SMR15は、バッテリ11の負極端子と正極端子のそれぞれに接続されており、SMR15の接続(オン)/遮断(オフ)が切り替えられることで、バッテリ11と電気負荷10との電気的な接続(オン)/遮断(オフ)が切り替えられる。   The SMR 15 is connected to each of the negative electrode terminal and the positive electrode terminal of the battery 11, and the connection (ON) / interruption (OFF) of the SMR 15 is switched, whereby the electrical connection (ON) between the battery 11 and the electric load 10 is performed. ) / Blocking (off).

電気負荷10は、例えばMG12(motor generator)、インバータ13、コンバータ14を備えている。SMR15がオンの際、バッテリ11の電力は、インバータ13及びコンバータ14で電力変換されてMG12に供給される。またMG12の回生エネルギでバッテリ11が充電される。   The electrical load 10 includes, for example, an MG 12 (motor generator), an inverter 13, and a converter 14. When the SMR 15 is on, the power of the battery 11 is converted by the inverter 13 and the converter 14 and supplied to the MG 12. Further, the battery 11 is charged with the regenerative energy of the MG 12.

バッテリ11と電気負荷10とはそれぞれ車両の車体100から絶縁されているが、バッテリ11と車体100との間には、絶縁抵抗Rg0及び浮遊容量Cg0からなる対地絶縁抵抗30が存在している。同様に電気負荷10と車体100との間にも、絶縁抵抗Rg1及び浮遊容量Cg1からなる対地絶縁抵抗31が存在している。なお図1では、バッテリ11と車体100とに絶縁抵抗Rg0が接続されており且つ絶縁抵抗Rg0に浮遊容量Cg0が並列接続されている状態と、電気負荷10と車体100とに絶縁抵抗Rg1が接続されており且つ絶縁抵抗Rg1に浮遊容量Cg1が並列接続された状態とを説明の便宜上示している。   The battery 11 and the electric load 10 are insulated from the vehicle body 100 of the vehicle, respectively. However, between the battery 11 and the vehicle body 100, a ground insulation resistance 30 including an insulation resistance Rg0 and a stray capacitance Cg0 exists. Similarly, a ground insulation resistance 31 including an insulation resistance Rg1 and a stray capacitance Cg1 exists between the electric load 10 and the vehicle body 100. In FIG. 1, the insulation resistance Rg0 is connected to the battery 11 and the vehicle body 100, and the floating resistance Cg0 is connected in parallel to the insulation resistance Rg0, and the insulation resistance Rg1 is connected to the electric load 10 and the vehicle body 100. For convenience of explanation, a state where the stray capacitance Cg1 is connected in parallel to the insulation resistance Rg1 is shown.

なお、バッテリ11に地絡が発生していない正常時には、対地絶縁抵抗30の絶縁抵抗Rg0は所定以上(例えば数MΩ以上)に維持される。一方、バッテリ11に地絡が発生している異常時には、対地絶縁抵抗30の絶縁抵抗Rg0が低下する。   When the ground fault does not occur in the battery 11, the insulation resistance Rg0 of the ground insulation resistance 30 is maintained at a predetermined value or more (for example, several MΩ or more). On the other hand, when the ground fault occurs in the battery 11, the insulation resistance Rg0 of the ground insulation resistance 30 decreases.

地絡判定装置2は、発振回路21、抵抗22、カップリングコンデンサ23、フィルタ24、差動増幅器25、制御装置26を備えている。   The ground fault determination device 2 includes an oscillation circuit 21, a resistor 22, a coupling capacitor 23, a filter 24, a differential amplifier 25, and a control device 26.

発振回路21は、所定の発振周波数の交流信号を出力する回路である。例えば発振回路21は、中心周波数fc=2Hz、波高値5Vの矩形波状の交流信号を出力する。   The oscillation circuit 21 is a circuit that outputs an AC signal having a predetermined oscillation frequency. For example, the oscillation circuit 21 outputs a rectangular wave AC signal having a center frequency fc = 2 Hz and a peak value of 5V.

抵抗22は、対地絶縁抵抗30と交流信号を分圧するものであり、一端が発振回路21に接続され、他端がカップリングコンデンサ23とフィルタ24との接続点Bに接続される。   The resistor 22 divides an AC signal from the ground insulation resistor 30, and one end is connected to the oscillation circuit 21 and the other end is connected to a connection point B between the coupling capacitor 23 and the filter 24.

カップリングコンデンサ23は、地絡判定装置2とバッテリ11との間で、直流成分を遮断して交流信号を通過させるための素子であり、一端が抵抗22に接続され、他端がバッテリ11の負極側に接続される。   The coupling capacitor 23 is an element for blocking a direct current component and allowing an alternating current signal to pass between the ground fault determination device 2 and the battery 11, one end of which is connected to the resistor 22, and the other end of the battery 11. Connected to the negative electrode side.

フィルタ24は、抵抗RとコンデンサCとを備えるアナログフィルタであり、例えば、後述する制御装置26で交流信号をA/D変換をする際にエイリアシングが発生することを抑制するためのアンチエイリアスフィルタとして設けられている。なお、フィルタ24は、制御装置26のサンプリング周波数(A/D変換周期の逆数)の半分以上の周波数成分を除去するように構成されている。   The filter 24 is an analog filter including a resistor R and a capacitor C. For example, the filter 24 is provided as an antialiasing filter for suppressing aliasing when an AC signal is A / D converted by the control device 26 described later. It has been. The filter 24 is configured to remove frequency components that are more than half of the sampling frequency (reciprocal of the A / D conversion period) of the control device 26.

差動増幅器25は、フィルタ24を通過後の交流信号について振幅レベルを調整するものであり、差動増幅器25を通過後の交流信号の振幅の最大値が所定値となるように基準電圧が定められている。例えば本実施形態において、発振回路21から出力される交流信号の振幅を5Vとした場合には、フィルタ24を通過後の交流信号の振幅の最大値が4.5Vとなるように、差動増幅器25によって交流信号の振幅が縮小される。   The differential amplifier 25 adjusts the amplitude level of the AC signal after passing through the filter 24, and the reference voltage is determined so that the maximum value of the amplitude of the AC signal after passing through the differential amplifier 25 becomes a predetermined value. It has been. For example, in the present embodiment, when the amplitude of the AC signal output from the oscillation circuit 21 is 5 V, the differential amplifier is set so that the maximum value of the amplitude of the AC signal after passing through the filter 24 is 4.5 V. 25 reduces the amplitude of the AC signal.

制御装置26は、A/D変換部28、CPU29の他、RAM、ROM、フラッシュメモリなどを備えて構成されており、ROMに記憶された各種プログラムをCPUが実行することで各種処理を行う。   The control device 26 is configured to include a RAM, a ROM, a flash memory, and the like in addition to the A / D conversion unit 28 and the CPU 29, and performs various processes when the CPU executes various programs stored in the ROM.

具体的には、制御装置26は、CPU29がA/D変換部28を介して入力された交流信号のデジタルフィルタ処理を実施し、そのフィルタ処理後の交流信号に基づいて、バッテリ11の地絡判定処理を実施する。デジタルフィルタ処理では、A/D変換後のデジタルの交流信号に含まれるノイズのうち、交流信号の周波数帯域から離れた周波数のノイズを除去する。例えば、有限インパルス応答(finite impulse response)によって、発振回路21から出力された交流信号の周波数帯域及びその周辺の帯域成分を濾過し、その他の周波数帯域の信号を遮断する。   Specifically, in the control device 26, the CPU 29 performs digital filter processing of the AC signal input via the A / D conversion unit 28, and the ground fault of the battery 11 is performed based on the AC signal after the filter processing. Perform the judgment process. In the digital filter processing, noise having a frequency away from the frequency band of the AC signal is removed from noise included in the digital AC signal after A / D conversion. For example, the frequency band of the AC signal output from the oscillation circuit 21 and the surrounding band components are filtered by a finite impulse response, and signals in other frequency bands are blocked.

また、地絡判定処理では、SMR15の切断状態で交流信号の波高値(振幅)を算出するとともに、その波高値と所定の地絡判定値との比較により地絡の有無を判定する。すなわち、制御装置26は、交流信号の波高値が地絡判定値以上となる場合、つまり対地絶縁抵抗30に対する抵抗22の分圧比率が低い場合には、地絡が発生していないと判定する。一方、交流信号の波高値が地絡判定値よりも低くなる場合、つまり対地絶縁抵抗30の低下に伴って、対地絶縁抵抗30に対する抵抗22の分圧比率が高くなる場合には、地絡が発生していると判定する。   In the ground fault determination process, the peak value (amplitude) of the AC signal is calculated in the disconnected state of the SMR 15, and the presence / absence of a ground fault is determined by comparing the peak value with a predetermined ground fault determination value. That is, the control device 26 determines that no ground fault has occurred when the peak value of the AC signal is equal to or greater than the ground fault determination value, that is, when the voltage dividing ratio of the resistor 22 to the ground insulation resistance 30 is low. . On the other hand, when the peak value of the AC signal is lower than the ground fault determination value, that is, when the voltage dividing ratio of the resistor 22 to the ground insulation resistance 30 increases as the ground insulation resistance 30 decreases, the ground fault occurs. It is determined that it has occurred.

本実施形態では特に、制御装置26による地絡判定に際して以下の3つの処理を実施することとしており、これら各処理の実施により、地絡判定の精度向上を図るものとしている。   In the present embodiment, in particular, the following three processes are performed when the ground fault is determined by the control device 26. By performing these processes, the accuracy of the ground fault determination is improved.

(1)地絡判定値の学習処理
(2)地絡判定パラメータの補正処理
(3)低周波ノイズ重畳時における無効化処理
以下、各処理について説明する。
(1) Ground fault determination value learning process (2) Ground fault determination parameter correction process (3) Invalidation process at the time of low frequency noise superimposition Each process will be described below.

<地絡判定値の学習処理>
バッテリ11の地絡判定では、一般に車両の工場出荷時に決定されている地絡判定値を用い、その地絡判定値と交流信号の波高値とに基づいて地絡の有無が判定される。ただし、バッテリ11の個体差や経年変化を考慮すると、対地絶縁抵抗30の抵抗値にはばらつきが生じていると考えられる。また、制御装置26に入力される交流信号についても、地絡判定装置2の各素子の個体差や劣化等によるばらつきが生じていると考えられる。ゆえに、こうしたばらつきに起因して、地絡判定の精度に影響が及ぶことが懸念される。
<Learning detection process for ground fault judgment value>
In the ground fault determination of the battery 11, a ground fault determination value generally determined when the vehicle is shipped from the factory is used, and the presence or absence of a ground fault is determined based on the ground fault determination value and the peak value of the AC signal. However, in consideration of individual differences and aging of the batteries 11, it is considered that the resistance value of the ground insulation resistance 30 varies. Further, it is considered that the AC signal input to the control device 26 also varies due to individual differences or deterioration of each element of the ground fault determination device 2. Therefore, there is a concern that the accuracy of the ground fault determination is affected due to such variation.

そこで本実施形態では、対地絶縁抵抗30の実抵抗値に対応する交流信号の波高値を時系列で検出し、その時系列の波高値に基づいて地絡判定値の学習を実施する。つまり、車両の使用時において所定条件の下で交流信号の波高値を検出するとともに、時系列の複数の波高値に基づいて地絡判定値を逐次設定する。   Therefore, in the present embodiment, the peak value of the AC signal corresponding to the actual resistance value of the ground insulation resistance 30 is detected in time series, and the ground fault determination value is learned based on the time series peak value. That is, the peak value of the AC signal is detected under a predetermined condition when the vehicle is used, and the ground fault determination value is sequentially set based on a plurality of time-series peak values.

より具体的には、制御装置26は、図2に示すように、車両の動作開始の都度(すなわち1トリップごとに)、交流信号の波高値pを検出するとともに、時系列のn個の波高値p1〜pnについて平均値を算出する。例えば、車両使用ごとに検出した交流信号の波高値pをフラッシュメモリ等に記憶しておき、今回及び過去のn回分の波高値の平均値を算出する。さらに、波高値の平均値から所定値αを減算して地絡判定値Aを算出する。本実施形態では、地絡判定値Aを学習値として記憶し、トリップごとに設定する。ただし、波高値の平均値を学習値として記憶することも可能である。そして、制御装置26は、学習値である地絡判定値を用い、都度の交流信号の波高値との比較に基づいて地絡の有無を判定する。   More specifically, as shown in FIG. 2, the control device 26 detects the peak value p of the alternating current signal each time the operation of the vehicle starts (that is, every trip), and time-series n waves. The average value is calculated for the high values p1 to pn. For example, the peak value p of the AC signal detected every time the vehicle is used is stored in a flash memory or the like, and the average value of the peak values for the current and past n times is calculated. Further, the ground fault determination value A is calculated by subtracting the predetermined value α from the average value of the peak values. In the present embodiment, the ground fault determination value A is stored as a learning value and set for each trip. However, it is also possible to memorize | store the average value of a crest value as a learning value. And the control apparatus 26 determines the presence or absence of a ground fault based on the comparison with the peak value of an alternating current signal using the ground fault determination value which is a learning value.

また、バッテリ11と電気負荷10とを接続するSMR15が閉じている状態と開いている状態とでは、抵抗22の分圧により検出される交流信号の波高値に差異が生じ、バッテリ11の地絡判定の精度に影響が及ぶ。そのため、本実施形態では、SMR15が開いている状態下で、都度の交流信号の波高値に基づいて地絡の有無を判定する。地絡判定値の学習処理においても、SMR15が開いている状態下で、時系列の複数の波高値に基づいて地絡判定値の学習を実施する。   Further, there is a difference in the peak value of the AC signal detected by the partial pressure of the resistor 22 between the closed state and the opened state of the SMR 15 that connects the battery 11 and the electric load 10, and the ground fault of the battery 11 occurs. The accuracy of the judgment is affected. Therefore, in the present embodiment, the presence or absence of a ground fault is determined based on the peak value of the AC signal each time while the SMR 15 is open. Also in the ground fault determination value learning process, the ground fault determination value is learned based on a plurality of time-series peak values with the SMR 15 open.

ここで、SMR15は、接続状態の切り替え時に発生する過渡電流の熱で溶着するなど、オン故障が生じる可能性がある。この場合、SMR15のオン故障が生じていると、バッテリ11と電気負荷10とが意図せず接続されたままの状態となるため、やはり地絡判定の精度に影響が及ぶ。   Here, there is a possibility that the SMR 15 may be turned on, such as being welded by heat of a transient current generated when the connection state is switched. In this case, if the on-failure of the SMR 15 occurs, the battery 11 and the electrical load 10 remain unintentionally connected, which also affects the accuracy of ground fault determination.

そこで本実施形態では、制御装置26は、地絡判定を実施する際に、SMR15がオン故障しているか否かを判定する。すなわち制御装置26は、上述した波高値の平均値に基づいてSMR異常判定用の異常判定値を設定し、その異常判定値と都度の交流信号の波高値との比較に基づいてSMR15のオン故障の有無を判定する。なお、地絡判定値とSMR異常判定値とは同じ値とすることが可能である。地絡判定値とSMR異常判定値とを共通の異常判定値とする場合、交流信号の波高値が異常判定値以下になることで、地絡及びSMRオン故障のいずれかの異常が発生していると判定される。そしてかかる場合には、SMR15を開閉(オン/オフ)させることで、地絡及びSMRオン故障のいずれが生じているかを特定する。つまり、SMR15をオン/オフさせて交流信号の波高値が変化すれば地絡が発生していると判定でき、変化しなければSMRオン故障が発生していると判定できる。SMR15のオン故障を適正に判定することで、地絡判定の精度向上も期待できる。   Therefore, in the present embodiment, the control device 26 determines whether or not the SMR 15 is on-failed when performing the ground fault determination. That is, the control device 26 sets an abnormality determination value for SMR abnormality determination based on the average value of the above-described peak values, and based on a comparison between the abnormality determination value and the peak value of each AC signal, the on-failure of the SMR 15 The presence or absence of is determined. The ground fault determination value and the SMR abnormality determination value can be the same value. When the ground fault determination value and the SMR abnormality determination value are set as a common abnormality determination value, either the ground fault or the SMR on failure occurs because the peak value of the AC signal is equal to or lower than the abnormality determination value. It is determined that In such a case, the SMR 15 is opened / closed (ON / OFF) to specify whether a ground fault or an SMR ON failure has occurred. That is, it can be determined that a ground fault has occurred if the peak value of the AC signal changes by turning on / off the SMR 15, and it can be determined that an SMR on failure has occurred if it does not change. By properly determining the on-failure of the SMR 15, an improvement in the accuracy of ground fault determination can be expected.

<地絡判定パラメータの補正処理>
バッテリ11の地絡判定は、交流信号の波高値を判定パラメータとして実施される。この場合、地絡の有無は対地絶縁抵抗30の絶縁抵抗Rg0の大きさに応じて判定されるものであるが、交流信号を用いて地絡判定を実施する場合には、浮遊容量Cg0による容量リアクタンスの影響で交流信号の波高値に変動が生じてしまう。この場合、絶縁抵抗Rg0が低下しておらず地絡が発生していないにもかかわらず、浮遊容量Cg0による容量リアクタンスの影響で地絡が誤判定されるおそれがある。
<Correction processing for ground fault determination parameter>
The ground fault determination of the battery 11 is performed using the peak value of the AC signal as a determination parameter. In this case, the presence or absence of a ground fault is determined according to the magnitude of the insulation resistance Rg0 of the ground insulation resistance 30, but when the ground fault determination is performed using an AC signal, the capacitance due to the stray capacitance Cg0 The peak value of the AC signal fluctuates due to the reactance. In this case, the ground fault may be erroneously determined due to the influence of the capacitive reactance due to the stray capacitance Cg0 even though the insulation resistance Rg0 is not lowered and the ground fault is not generated.

そこで、本実施形態では浮遊容量Cg0の容量リアクタンスによる電圧誤差を取り除いた状態で地絡判定を実施する。すなわち、浮遊容量Cg0の容量リアクタンスが交流信号の周波数に応じて変化することを利用して、地絡判定パラメータである交流信号の波高値の検出値を補正する。   Therefore, in the present embodiment, the ground fault determination is performed in a state where the voltage error due to the capacitive reactance of the stray capacitance Cg0 is removed. That is, using the fact that the capacitive reactance of the stray capacitance Cg0 changes according to the frequency of the AC signal, the detected value of the peak value of the AC signal, which is a ground fault determination parameter, is corrected.

絶縁抵抗値と交流信号の波高値とは図3に示す関係にあり、絶縁抵抗値が大きいほど波高値が大きくなる。図3において、第1波高値V1は、発振回路21の中心周波数fcが地絡判定用の第1周波数f1の場合における絶縁抵抗Rg0及び浮遊容量Cg0により生じる振幅分を示している。第2波高値V2は、発振回路21の中心周波数fcが第1周波数f1とは異なる第2周波数f2の場合における絶縁抵抗Rg0及び浮遊容量Cg0により生じる振幅分を示している。この場合、制御装置26は、第1波高値V1と第2波高値V2との差ΔV(=V1−V2)を算出し、その差ΔVを地絡判定パラメータとして用いて地絡判定を実施する。なお、SMR異常判定に関していえば、差ΔVをSMR異常判定パラメータとして用いてSMR異常判定を実施する。   The insulation resistance value and the peak value of the AC signal are in the relationship shown in FIG. 3, and the peak value increases as the insulation resistance value increases. In FIG. 3, the first peak value V1 indicates an amplitude component generated by the insulation resistance Rg0 and the stray capacitance Cg0 when the center frequency fc of the oscillation circuit 21 is the first frequency f1 for ground fault determination. The second peak value V2 indicates an amplitude generated by the insulation resistance Rg0 and the stray capacitance Cg0 when the center frequency fc of the oscillation circuit 21 is the second frequency f2 different from the first frequency f1. In this case, the control device 26 calculates the difference ΔV (= V1−V2) between the first peak value V1 and the second peak value V2, and performs the ground fault determination using the difference ΔV as the ground fault determination parameter. . Regarding the SMR abnormality determination, the SMR abnormality determination is performed using the difference ΔV as the SMR abnormality determination parameter.

具体的には、図4に示すように、交流信号の中心周波数fcを第1周波数f1から第2周波数f2に変化させた際に、浮遊容量Cg0の容量リアクタンスの変化に伴い交流電圧が第1波高値V1から第2波高値V2に変わることを利用して、第1波高値V1及び第2波高値V2の差ΔVから浮遊容量Cg0を推定する。そして、推定された浮遊容量Cg0を用いて第1波高値V1を補正する。   Specifically, as shown in FIG. 4, when the center frequency fc of the AC signal is changed from the first frequency f1 to the second frequency f2, the AC voltage is changed according to the change in the capacitive reactance of the stray capacitance Cg0. Utilizing the change from the peak value V1 to the second peak value V2, the stray capacitance Cg0 is estimated from the difference ΔV between the first peak value V1 and the second peak value V2. Then, the first peak value V1 is corrected using the estimated stray capacitance Cg0.

例えば、ROMには差ΔVから浮遊容量Cg0を算出するための演算式やマップなどの情報が記憶されており、CPU29はこれらの演算を用いて浮遊容量Cg0の推定値を算出する。そして、浮遊容量Cg0の推定値を用いて、第1周波数f1での容量インピーダンスZcを算出し、第1波高値V1から容量インピーダンスZcで生じる電圧誤差を差し引くことで、補正後の波高値V11を得る。なお、交流信号の第1周波数f1は例えば2〜10Hzの範囲で設定される。第2周波数f2は、第1周波数f1よりも高い周波数であり、例えば4Hz〜100Hzの範囲で設定される。   For example, information such as an arithmetic expression and a map for calculating the stray capacitance Cg0 from the difference ΔV is stored in the ROM, and the CPU 29 calculates an estimated value of the stray capacitance Cg0 using these calculations. Then, using the estimated value of the stray capacitance Cg0, the capacitance impedance Zc at the first frequency f1 is calculated, and the corrected peak value V11 is obtained by subtracting the voltage error caused by the capacitance impedance Zc from the first peak value V1. obtain. The first frequency f1 of the AC signal is set in the range of 2 to 10 Hz, for example. The second frequency f2 is a frequency higher than the first frequency f1, and is set in the range of 4 Hz to 100 Hz, for example.

<低周波ノイズ重畳時における無効化処理>
車体100とバッテリ11との間には浮遊容量Cg0が存在しているため、電気負荷10の状態変化などで生じたコモンモードノイズが、浮遊容量Cg0を介して地絡判定装置2に侵入する可能性がある。このコモンモードノイズの周波数が、発振回路21から出力される交流信号の周波数帯域に近い又は重畳する場合には、制御装置26のデジタルフィルタ処理でそのノイズを除去することができず、地絡判定の精度に影響してしまう。
<Disabling process when low frequency noise is superimposed>
Since the stray capacitance Cg0 exists between the vehicle body 100 and the battery 11, common mode noise generated due to a change in the state of the electric load 10 can enter the ground fault determination device 2 via the stray capacitance Cg0. There is sex. When the frequency of the common mode noise is close to or superimposed on the frequency band of the AC signal output from the oscillation circuit 21, the noise cannot be removed by the digital filter processing of the control device 26, and ground fault determination Will affect the accuracy of.

そこで本実施形態では、制御装置26は、発振回路21の発振周波数よりも高周波で、かつフィルタ24で除去できない低周波ノイズがフィルタ24を通過した後交流信号に重畳しているか否かを判定し、ノイズ重畳状態である場合に、交流信号の波高値に基づく地絡判定を無効化する。つまり、交流信号と分離できない周波数のノイズが交流信号に重畳されている場合には、その交流信号を地絡判定に使用しないようにする。これにより地絡の誤判定の発生を抑え、地絡判定の精度を高めるようにする。   Therefore, in the present embodiment, the control device 26 determines whether or not low frequency noise that is higher than the oscillation frequency of the oscillation circuit 21 and cannot be removed by the filter 24 is superimposed on the AC signal after passing through the filter 24. When the noise is superimposed, the ground fault determination based on the peak value of the AC signal is invalidated. That is, when noise having a frequency that cannot be separated from the AC signal is superimposed on the AC signal, the AC signal is not used for the ground fault determination. This suppresses the occurrence of erroneous ground fault determination and increases the accuracy of ground fault determination.

すなわち、図1において、制御装置26は、A/D変換部28と、CPU29とを有しており、CPU29はデジタルフィルタ27を有する。制御装置26に入力されたアナログの交流信号は、A/D変換部28でA/D変換されてデジタルの交流信号に変換される。A/D変換後のデジタルの交流信号は、デジタルフィルタ27に入力される。デジタルフィルタ27は、発振回路21の発振周波数の交流信号を通過させる。   That is, in FIG. 1, the control device 26 includes an A / D conversion unit 28 and a CPU 29, and the CPU 29 includes a digital filter 27. The analog AC signal input to the control device 26 is A / D converted by the A / D converter 28 and converted into a digital AC signal. The digital AC signal after A / D conversion is input to the digital filter 27. The digital filter 27 passes an AC signal having the oscillation frequency of the oscillation circuit 21.

発振回路21の発振周波数に近い又は重複する周波数の低周波ノイズが交流信号に含まれていると、その低周波ノイズもデジタルフィルタ27を通過してしまうため、交流信号から低周波ノイズが除去されない。この場合、低周波ノイズの影響で波高値が変動した交流信号に基づき地絡判定が実施されるため、地絡判定の精度が低下してしまう。   If low frequency noise having a frequency close to or overlapping with the oscillation frequency of the oscillation circuit 21 is included in the AC signal, the low frequency noise also passes through the digital filter 27, so that the low frequency noise is not removed from the AC signal. . In this case, since the ground fault determination is performed based on the AC signal whose peak value fluctuates due to the low frequency noise, the accuracy of the ground fault determination is lowered.

そこで、本実施形態では発振回路21から出力される交流信号の波高値(振幅)を、A/D変換部28の入力電圧範囲と同じ又はそれよりも大きい振幅とし、その交流信号の振幅を差動増幅器25で縮小する。これにより所定の入力電圧範囲(例えば0〜5V)を有するA/D変換部28において、入力電圧範囲の上限側に、A/D変換部28通過後の交流信号が入力電圧範囲を超えるものであることを判定する超過判定領域(4.5V〜5V)を形成する。そして、交流信号の波高値が超過判定領域に含まれる場合に、交流信号にデジタルフィルタ27で除去できない低周波のノイズが重畳された状態であるとして、その交流信号を地絡判定に使用しないようにする。   Therefore, in this embodiment, the peak value (amplitude) of the AC signal output from the oscillation circuit 21 is set to an amplitude that is the same as or larger than the input voltage range of the A / D converter 28, and the amplitude of the AC signal is different. Reduction is performed by the dynamic amplifier 25. Thereby, in the A / D converter 28 having a predetermined input voltage range (for example, 0 to 5 V), the AC signal after passing through the A / D converter 28 exceeds the input voltage range on the upper limit side of the input voltage range. An excess determination region (4.5 V to 5 V) for determining the presence is formed. When the peak value of the AC signal is included in the excess determination region, the AC signal is not used for the ground fault determination on the assumption that the low-frequency noise that cannot be removed by the digital filter 27 is superimposed on the AC signal. To.

具体的には図5に示されるように、CPU29は、デジタルフィルタ27通過後の交流信号の波高値と、超過判定領域の上限値(4.5V)とを比較して、交流電圧の波高値が上限値を超えて超過判定領域に含まれる回数が単位時間内に複数回ある場合に、その交流信号を地絡判定に使用しない(無効化する)と判定する。又は、交流信号の電圧の立ち上がりのエッジが超過判定領域に含まれる回数が単位時間内に複数回ある場合に、その交流信号を地絡判定に使用しないと判定してもよい。   Specifically, as shown in FIG. 5, the CPU 29 compares the peak value of the AC signal after passing through the digital filter 27 with the upper limit value (4.5 V) of the excess determination region, and the peak value of the AC voltage. Exceeds the upper limit value and is included in the excess determination region a plurality of times within a unit time, it is determined that the AC signal is not used (deactivated) for ground fault determination. Alternatively, when the rising edge of the voltage of the AC signal is included in the excess determination region a plurality of times within the unit time, it may be determined that the AC signal is not used for the ground fault determination.

次に以上の構成を備える地絡判定装置の処理について説明する。なお以下の処理は、図示を略す車両のイグニッションスイッチがオンとされた状態で、制御装置26のCPU29が実施する。なお初期設定として、発振回路21から出力される交流信号の周波数は、第1周波数f1=2Hzに設定されており、これに合わせてデジタルフィルタ27が通過する周波数帯域が設定されているとする。   Next, the process of a ground fault determination apparatus provided with the above structure is demonstrated. The following processing is performed by the CPU 29 of the control device 26 in a state where an ignition switch of a vehicle (not shown) is turned on. As an initial setting, it is assumed that the frequency of the AC signal output from the oscillation circuit 21 is set to the first frequency f1 = 2 Hz, and the frequency band through which the digital filter 27 passes is set accordingly.

図6において、ステップS10でSMR15がオフであるか否かを判定する。例えば車両の始動時などSMR15がオフとなる場合に肯定判定する。肯定判定した場合には、ステップS11で交流信号のA/D値を取得する。すなわちアナログの交流信号をデジタルの交流信号に変換する。ステップS12では、デジタルフィルタ処理を実施する。すなわち、A/D変換後の交流信号の発振周波数の周波数成分を通過する。これにより第1周波数f1における第1波高値V1を取得する。   In FIG. 6, it is determined in step S10 whether or not the SMR 15 is off. For example, an affirmative determination is made when the SMR 15 is turned off, such as when the vehicle is started. If the determination is affirmative, the A / D value of the AC signal is acquired in step S11. That is, an analog AC signal is converted into a digital AC signal. In step S12, digital filter processing is performed. That is, it passes the frequency component of the oscillation frequency of the AC signal after A / D conversion. Thus, the first peak value V1 at the first frequency f1 is acquired.

ステップS13では、交流信号を地絡判定に使用するか否かを判定する。ここでは、デジタルフィルタ27を通過後の交流信号の波高値が超過判定領域に含まれる回数が、単位時間内に所定未満の場合に、交流信号を地絡判定に使用すると肯定判定する。   In step S13, it is determined whether or not the AC signal is used for ground fault determination. Here, when the number of times the peak value of the AC signal after passing through the digital filter 27 is included in the excess determination region is less than a predetermined value within the unit time, an affirmative determination is made when the AC signal is used for ground fault determination.

ステップS13で肯定判定した場合には、ステップS14で、浮遊容量Cg0による電圧誤差を補正するために、第1周波数f1とは異なる第2周波数f2での交流信号の第2波高値V2を取得済みであるか否かを判定する。   If an affirmative determination is made in step S13, the second peak value V2 of the AC signal at the second frequency f2 different from the first frequency f1 has been acquired in step S14 in order to correct the voltage error due to the stray capacitance Cg0. It is determined whether or not.

ステップS14で否定判定した場合には、ステップS18に進み、発振回路21の第2周波数f2に変更する。例えば第2周波数f2=20Hzに設定する。また発振回路21の周波数変更に合わせて、デジタルフィルタ27が通過する周波数帯域を設定する。ステップS19では、第2周波数f2の場合における交流信号の第2波高値V2を検出する。   If a negative determination is made in step S14, the process proceeds to step S18 to change to the second frequency f2 of the oscillation circuit 21. For example, the second frequency f2 = 20 Hz is set. Further, the frequency band through which the digital filter 27 passes is set in accordance with the frequency change of the oscillation circuit 21. In step S19, the second peak value V2 of the AC signal at the second frequency f2 is detected.

ステップS14で肯定判定した場合には、ステップS15で、第1周波数f1での第1波高値V1を補正して、補正後の波高値V11を算出する。すなわち、差ΔVから浮遊容量Cg0を推定し、浮遊容量Cg0の推定値を用いて第1周波数f1での容量インピーダンスZcを算出する。そして第1周波数f1の際に容量インピーダンスZcで生じる電圧誤差を差し引くことで、補正後の波高値V11を得る。   If an affirmative determination is made in step S14, in step S15, the first peak value V1 at the first frequency f1 is corrected, and the corrected peak value V11 is calculated. That is, the stray capacitance Cg0 is estimated from the difference ΔV, and the capacitance impedance Zc at the first frequency f1 is calculated using the estimated value of the stray capacitance Cg0. Then, a corrected peak value V11 is obtained by subtracting a voltage error caused by the capacitive impedance Zc at the first frequency f1.

ステップS16では、補正後の波高値V11が地絡判定値A以上であるか否かを判定する。肯定判定した場合には、ステップS16で地絡判定値Aの学習処理をする。すなわち、図2に示されるように、ステップS12で取得した交流信号の波高値を含めたn回分の波高値の平均値を算出して、地絡判定値Aを設定する。なお今回設定された地絡判定値Aは、次回の地絡判定の際の判定基準に使用される。   In step S16, it is determined whether or not the corrected peak value V11 is equal to or greater than the ground fault determination value A. If the determination is affirmative, the ground fault determination value A is learned in step S16. That is, as shown in FIG. 2, an average value of n peak values including the peak value of the AC signal acquired in step S12 is calculated, and the ground fault determination value A is set. The ground fault determination value A set this time is used as a determination criterion for the next ground fault determination.

ステップS16で否定判定した場合、ステップS20に進み、SMR15を開閉(オンオフ)させて、その際の交流信号の波高値の変化を検出する。ステップS21では、SMR15が正常か否かを判定する。すなわちSMR15のオンオフに伴い交流信号の波高値が変化した場合には、SMR15は正常であると判定する。一方、SMR25のオンオフに伴い交流信号の波高値が変化しなかった場合には、SMR15は異常であると判定する。   When a negative determination is made in step S16, the process proceeds to step S20, where the SMR 15 is opened and closed (on / off), and a change in the peak value of the AC signal at that time is detected. In step S21, it is determined whether the SMR 15 is normal. That is, when the peak value of the AC signal changes as SMR 15 is turned on / off, it is determined that SMR 15 is normal. On the other hand, when the peak value of the AC signal does not change as SMR 25 is turned on / off, it is determined that SMR 15 is abnormal.

ステップS21でSMR15が正常の場合には、ステップS22で地絡異常であると判定する。この場合、地絡異常が生じている旨の情報を出力する。ステップS21でSMR15が異常の場合には、ステップS23でSMR15のオン故障であると判定する。この場合、SMR15にオン故障が生じている旨の情報を出力する。なおステップS10,S13で否定判定した場合には処理を終了する。   If SMR 15 is normal in step S21, it is determined in step S22 that the ground fault is abnormal. In this case, information indicating that a ground fault abnormality has occurred is output. If the SMR 15 is abnormal in step S21, it is determined in step S23 that the SMR 15 is on. In this case, information indicating that an on failure has occurred in the SMR 15 is output. If a negative determination is made in steps S10 and S13, the process ends.

次に図7のタイミングチャートを用いて上記処理の実行例を説明する。なお以下の処理はIGスイッチがオンの際に、所定の周期で繰り返し実施される。なお初期状態ではSMR15はオフであり、発振回路21からは第1周波数f1の交流信号が出力される。   Next, an example of execution of the above process will be described using the timing chart of FIG. The following processing is repeatedly performed at a predetermined cycle when the IG switch is on. In the initial state, the SMR 15 is off, and the oscillation circuit 21 outputs an AC signal having the first frequency f1.

時刻t1でIGスイッチがオンとされると、発振回路21から第1周波数f1(=2Hz)の交流信号が出力される。また制御装置26の処理が開始されて、交流信号のA/D変換や、デジタルフィルタ27でのノイズ除去が実施され、第1波高値V1が検出される。   When the IG switch is turned on at time t1, the oscillation circuit 21 outputs an AC signal having the first frequency f1 (= 2 Hz). Moreover, the process of the control apparatus 26 is started, A / D conversion of an alternating current signal and the noise removal by the digital filter 27 are implemented, and the 1st peak value V1 is detected.

この際、第1波高値V1が超過判定領域に含まれる頻度が所定以上の場合には、ノイズが重畳された状態であり、その交流信号を用いた処理を実施しない無効化処理が実施される。この際、第1波高値V1がノイズ重畳状態であることを示す信号が出力されてもよい。第1波高値V1が超過判定領域に含まれる頻度が所定未満の場合には、その交流信号を地絡判定に使用すると判定される。   At this time, if the frequency at which the first peak value V1 is included in the excess determination region is greater than or equal to a predetermined value, noise is superimposed and invalidation processing that does not perform processing using the AC signal is performed. . At this time, a signal indicating that the first peak value V1 is in a noise superimposed state may be output. When the frequency at which the first peak value V1 is included in the excess determination region is less than a predetermined value, it is determined that the AC signal is used for ground fault determination.

交流信号を地絡判定に使用すると判定された場合、発振回路21の第1周波数f1からf2に一旦変更され、その際の交流信号の第2波高値V2が検出される。そして交流信号の波高値の差ΔVから、浮遊容量Cg0が推定され、浮遊容量Cg0の推定値を用いて補正後の波高値V11が算出される。   When it is determined that the AC signal is used for ground fault determination, the first frequency f1 of the oscillation circuit 21 is temporarily changed from f1 to f2, and the second peak value V2 of the AC signal at that time is detected. The stray capacitance Cg0 is estimated from the peak value difference ΔV of the AC signal, and the corrected peak value V11 is calculated using the estimated value of the stray capacitance Cg0.

補正後の波高値V11が地絡判定値A以上であると判定されると、すなわち地絡が発生していないと判定されると、今回取得した交流信号の波高値を含めたn回分の波高値の平均値が算出される。この場合、次回の地絡判定の際に、更新済の地絡判定値Aが使用される。   When it is determined that the corrected peak value V11 is greater than or equal to the ground fault determination value A, that is, when it is determined that a ground fault has not occurred, the waves for n times including the peak value of the AC signal acquired this time The average of the high values is calculated. In this case, the updated ground fault determination value A is used in the next ground fault determination.

一方、波高値V11が地絡判定値A未満と判定された場合には、SMR15が開閉されて、交流信号の波高値の変化が検出される。この際、SMR15を動かしても交流信号の波高値が変動しなかったことが検出された場合には、SMR15のオン故障異常が判定される。一方、交流信号の波高値が変動した場合には、地絡異常と判定される。   On the other hand, when it is determined that the peak value V11 is less than the ground fault determination value A, the SMR 15 is opened and closed, and a change in the peak value of the AC signal is detected. At this time, if it is detected that the peak value of the AC signal does not fluctuate even when the SMR 15 is moved, it is determined that the SMR 15 has an on failure. On the other hand, when the peak value of the AC signal varies, it is determined that the ground fault is abnormal.

SMR15が正常と判定された場合、時刻t2で図示を略す上位ECUからの指令信号を受けて、SMR15がオンに切り替えられる。なおSMR15の接続/遮断は、正極側と負極側のSMR15が同時に切り替えられてもよく、片側ずつ順番に切り替えられてもよい。   When it is determined that the SMR 15 is normal, the SMR 15 is switched on in response to a command signal from a host ECU (not shown) at time t2. The connection / disconnection of the SMR 15 may be switched simultaneously between the positive side and the negative side SMR 15, or may be switched in order one by one.

そして、IGスイッチ及びSMR15の両方がオンとなると、バッテリ11と電気負荷10とが電気的に接続され車両走行が可能な状態となる。この際、図示を略すアクセルセンサからの検出信号に基づきMGの駆動が制御されて車両が走行する。   When both the IG switch and the SMR 15 are turned on, the battery 11 and the electric load 10 are electrically connected to enable vehicle travel. At this time, the driving of the MG is controlled based on a detection signal from an accelerator sensor (not shown), and the vehicle travels.

そして時刻t3で、IGオフに切り替えられた後、時刻t4でSMR15がオフに切り替えられる。   Then, after the IG is switched off at time t3, the SMR 15 is switched off at time t4.

上記によれば以下の優れた効果を奏することができる。   According to the above, the following excellent effects can be achieved.

・例えば製品の製造時に決定されている地絡判定値を用いてバッテリ11の地絡判定を実施する場合、バッテリ11の個体差や経年劣化などに伴う対地絶縁抵抗30のばらつきや、地絡判定装置2の各素子の個体差や劣化によるばらつきなどが生じていると、それが、地絡判定の精度に影響してしまう。そこで、地絡判定装置2で検出した交流信号の波高値を用いて地絡判定値を設定する。この場合、バッテリ11や地絡判定装置2の個体差や経年劣化などに起因する地絡判定の誤差を抑えることができ、地絡判定の精度を高めることができる。   For example, when the ground fault determination of the battery 11 is performed using the ground fault determination value determined at the time of manufacture of the product, the variation in the ground insulation resistance 30 due to the individual difference of the battery 11 or aging deterioration, or the ground fault determination If there is an individual difference or a variation due to deterioration of each element of the device 2, it affects the accuracy of the ground fault determination. Therefore, the ground fault determination value is set using the peak value of the AC signal detected by the ground fault determination device 2. In this case, it is possible to suppress an error in ground fault determination due to individual differences of the battery 11 and the ground fault determination device 2, deterioration over time, and the like, and it is possible to improve the accuracy of ground fault determination.

・バッテリ11と電気負荷10とを接続するSMR15の開閉状態によって、抵抗22の分圧により検出される交流信号の波高値に差が生じ、バッテリ11の地絡判定の精度に影響が及ぶ。そこでSMR15が開状態の際に取得した交流信号の波高値を用いて地絡判定値を更新することで、より適切なる地絡判定の実施が可能となる。   Depending on the open / closed state of the SMR 15 that connects the battery 11 and the electric load 10, a difference occurs in the peak value of the AC signal detected by the partial pressure of the resistor 22, which affects the accuracy of the ground fault determination of the battery 11. Therefore, by updating the ground fault determination value using the peak value of the AC signal acquired when the SMR 15 is in the open state, more appropriate ground fault determination can be performed.

・SMR15は接続状態の切替時などに発生する熱で溶着などによるオン故障が生じうる。SMR15のオン故障が生じると、バッテリ11と電気負荷10とが意図せずに接続状態のままとなるため、地絡判定の精度に影響が及ぶ。すなわち、オン故障が生じた場合にも、交流電圧の波高値が低下してしまうため、地絡が生じていると誤判定されるおそれがある。そこでバッテリ11が地絡していると判定された際、SMR15を駆動して交流信号の波高値が変化したか否かに応じてSMR15のオン故障を判定する。この場合、地絡であるかSMR15のオン故障であるかを特定することができ、地絡判定の精度を高めることができる。   The SMR 15 may be turned on due to welding due to heat generated when the connection state is switched. When an on failure of the SMR 15 occurs, the battery 11 and the electrical load 10 are unintentionally left in a connected state, which affects the accuracy of ground fault determination. That is, even when an on-failure occurs, the peak value of the AC voltage decreases, and therefore it may be erroneously determined that a ground fault has occurred. Therefore, when it is determined that the battery 11 is grounded, the SMR 15 is driven to determine whether the SMR 15 is on or not depending on whether the peak value of the AC signal has changed. In this case, it is possible to specify whether it is a ground fault or an SMR 15 on failure, and the accuracy of the ground fault determination can be improved.

・バッテリ11に地絡が生じていないと判定された際の波高値を用いて地絡判定値が設定され、その地絡判定値により地絡判定が行われるため、地絡判定を適切に実施できる。   ・ The ground fault determination value is set using the peak value when it is determined that no ground fault has occurred in the battery 11, and the ground fault determination is performed based on the ground fault determination value. it can.

・車両の使用に応じて経年劣化が生じても、それに対する適切な対処が可能となる。   -Even if aged deterioration occurs depending on the use of the vehicle, it is possible to take appropriate measures against it.

また本実施形態は、上記に限定されず以下のように実施されてもよい。   The present embodiment is not limited to the above, and may be implemented as follows.

・上記では、波高値V11が地絡判定値A未満となった場合に、SMR15を開閉させて地絡かSMR15のオン故障かを判別している。これ以外にも、地絡判定用の判定基準とSMR15のオン故障判定用の判定基準とを個別に設けて、波高値V11と各判定基準との比較により、地絡又はSMR15のオン故障が判定されてもよい。   In the above description, when the peak value V11 becomes less than the ground fault determination value A, the SMR 15 is opened and closed to determine whether it is a ground fault or an SMR 15 on failure. In addition, a ground fault determination criterion and an SMR 15 on-failure determination criterion are individually provided, and a ground fault or an SMR 15 on-failure is determined by comparing the peak value V11 with each criterion. May be.

・SMR15に溶着などのオン故障が生じている場合には、バッテリ11の対地絶縁抵抗30と電気負荷10の対地絶縁抵抗31とが並列接続状態となり、地絡判定装置2による地絡判定を実施する場合における容量インピーダンスが浮遊容量Cg1によって変わる。そこで、容量インピーダンスが発振回路21の周波数に応じて変わることを利用して、SMR15のオン故障の有無を判定してもよい。すなわち、SMR15がオフの際に発振回路21の発振周波数を変化させる。この際、SMR15にオン故障が生じていると、SMR15にオン故障が生じていない場合に比べて、浮遊容量Cg1による容量インピーダンスの変動分だけ、交流信号の波高値の変化が大きくなる。そこで、SMR15をオンオフした際の交流信号の波高値の変動の大きさを利用して、SMR15のオン故障を判定してもよい。   When an on failure such as welding occurs in the SMR 15, the ground insulation resistance 30 of the battery 11 and the ground insulation resistance 31 of the electric load 10 are connected in parallel, and the ground fault determination is performed by the ground fault determination device 2. In this case, the capacitance impedance varies depending on the stray capacitance Cg1. Therefore, the presence / absence of an on failure of the SMR 15 may be determined using the fact that the capacitance impedance changes according to the frequency of the oscillation circuit 21. That is, the oscillation frequency of the oscillation circuit 21 is changed when the SMR 15 is off. At this time, if an on-failure has occurred in the SMR 15, the change in the peak value of the AC signal is increased by the amount of variation in the capacitance impedance due to the stray capacitance Cg 1, compared to the case where no on-failure has occurred in the SMR 15. Therefore, the on-failure of the SMR 15 may be determined using the magnitude of fluctuation of the peak value of the AC signal when the SMR 15 is turned on / off.

・上記では、時系列のn個の波高値について地絡判定値Aを算出しているが、車両の使用開始から取得した全波高値について地絡判定値Aを算出してもよい。   In the above description, the ground fault determination value A is calculated for n time-series peak values, but the ground fault determination value A may be calculated for all peak values acquired from the start of use of the vehicle.

・図6において、例えばステップS10の後に、インバータ13等の電気負荷10が動作していないか否かが判定されてもよい。この場合、電気負荷10の動作状態で地絡判定が実施されることを回避できる。   In FIG. 6, for example, after step S <b> 10, it may be determined whether or not the electrical load 10 such as the inverter 13 is operating. In this case, it can be avoided that the ground fault determination is performed in the operating state of the electric load 10.

・上記において、IGオフとなった後に、SMR15がオフに切り替えられているが、MR15がオフとなった後、IGオフに切り替えられてもよい。   In the above description, the SMR 15 is switched off after the IG is turned off. However, the IG may be switched off after the MR 15 is turned off.

・上記では、浮遊容量Cg0の推定値を用いて、補正後の波高値V11を算出する例を示した。これ以外にも差ΔVを用いて補正後の波高値V11が直接算出されてもよい。この場合、ROMには差ΔVから補正後の波高値V11を算出するための演算式やマップ等が記憶される。   In the above, an example in which the corrected peak value V11 is calculated using the estimated value of the stray capacitance Cg0 is shown. In addition to this, the corrected peak value V11 may be directly calculated using the difference ΔV. In this case, the ROM stores an arithmetic expression, a map, and the like for calculating the corrected peak value V11 from the difference ΔV.

・上記では、車両の動作開始の都度に、交流信号の波高値pを検出するとしたが、車両の動作終了時の都度に、交流信号の波高値pが検出されてもよい。又は車両の動作開始時及び終了時の両方において交流信号の波高値pを検出して、これらを用いて地絡判定値が設定されてもよい。   In the above description, the peak value p of the AC signal is detected every time the operation of the vehicle starts. However, the peak value p of the AC signal may be detected every time the operation of the vehicle ends. Alternatively, the peak value p of the AC signal may be detected both at the start and end of the operation of the vehicle, and the ground fault determination value may be set using these.

1…高電圧回路、21…発振回路、23…カップリングコンデンサ、26…制御装置。   DESCRIPTION OF SYMBOLS 1 ... High voltage circuit, 21 ... Oscillator circuit, 23 ... Coupling capacitor, 26 ... Control apparatus.

Claims (6)

高電圧部(11)の対地絶縁抵抗(30)に印加される所定の発振周波数の交流信号を出力する交流信号出力手段(21)と、
前記交流信号出力手段と前記対地絶縁抵抗との間に設けられたカップリングコンデンサ(23)と、
前記交流信号出力手段と前記カップリングコンデンサとの間で前記交流信号を取り込み、当該交流信号の波高値を算出する波高値算出手段(26)と、
前記波高値算出手段により算出した前記波高値と所定の地絡判定値との比較により前記高電圧部の地絡判定を実施する地絡判定手段(26)と、
前記交流信号の波高値が前記地絡判定値よりも大きく、前記地絡判定手段が地絡が発生していないと判定する所定条件成立した際にその地絡判定に使用した前記交流信号の波高値を用いて、前記地絡判定手段による次回の地絡判定の際の前記地絡判定値を設定する判定値設定手段(26)と、
を備えることを特徴とする地絡判定装置。
AC signal output means (21) for outputting an AC signal having a predetermined oscillation frequency applied to the ground insulation resistance (30) of the high voltage section (11);
A coupling capacitor (23) provided between the AC signal output means and the ground insulation resistance;
A peak value calculating means (26) for taking in the AC signal between the AC signal output means and the coupling capacitor and calculating a peak value of the AC signal;
A ground fault determination means (26) for performing a ground fault determination of the high voltage portion by comparing the peak value calculated by the peak value calculation means and a predetermined ground fault determination value;
The AC signal used for the ground fault determination when the peak value of the AC signal is larger than the ground fault determination value and a predetermined condition is determined that the ground fault determination means determines that no ground fault has occurred. using the peak value, the determination value setting means for setting said destination絡判value during the next ground determining by the grounding determination means (26),
A ground fault determination device comprising:
前記高電圧部と前記高電圧部の電力が供給される電気負荷(10)との電気的な接続状態を切り替える切替手段(15)を備え、
前記判定値設定手段は、前記切替手段がオフの際に前記波高値算出手段により算出した前記交流信号の波高値を用いて、前記地絡判定値を設定する請求項1に記載の地絡判定装置。
Comprising a switching means (15) for switching an electrical connection state between the high voltage section and an electric load (10) to which power of the high voltage section is supplied,
2. The ground fault determination according to claim 1, wherein the determination value setting unit sets the ground fault determination value using a peak value of the AC signal calculated by the peak value calculation unit when the switching unit is off. apparatus.
前記地絡判定手段は、前記波高値算出手段で算出した前記波高値が前記地絡判定値以下となる場合に、前記切替手段を開閉させ、その開閉により、前記波高値が変化した場合には地絡であると判定し、前記波高値が変化しなかった場合には前記切替手段のオン故障であると判定する請求項2に記載の地絡判定装置。   The ground fault determination means opens and closes the switching means when the peak value calculated by the peak value calculation means is less than or equal to the ground fault determination value, and when the peak value changes due to the opening and closing. The ground fault determination apparatus according to claim 2, wherein it is determined that a ground fault has occurred, and if the peak value has not changed, it is determined that the switching unit has an on failure. 高電圧部(11)の対地絶縁抵抗(30)に印加される所定の発振周波数の交流信号を出力する交流信号出力手段(21)と、AC signal output means (21) for outputting an AC signal having a predetermined oscillation frequency applied to the ground insulation resistance (30) of the high voltage section (11);
前記交流信号出力手段と前記対地絶縁抵抗との間に設けられたカップリングコンデンサ(23)と、A coupling capacitor (23) provided between the AC signal output means and the ground insulation resistance;
前記交流信号出力手段と前記カップリングコンデンサとの間で前記交流信号を取り込み、当該交流信号の波高値を算出する波高値算出手段(26)と、A peak value calculating means (26) for taking in the AC signal between the AC signal output means and the coupling capacitor and calculating a peak value of the AC signal;
前記波高値算出手段により算出した前記波高値と所定の地絡判定値との比較により前記高電圧部の地絡判定を実施する地絡判定手段(26)と、A ground fault determination means (26) for performing a ground fault determination of the high voltage portion by comparing the peak value calculated by the peak value calculation means and a predetermined ground fault determination value;
所定条件の成立に応じて、前記波高値算出手段により算出した時系列の波高値を用いて、前記地絡判定値を設定する判定値設定手段(26)と、A determination value setting means (26) for setting the ground fault determination value using a time-series peak value calculated by the peak value calculation means according to establishment of a predetermined condition;
前記高電圧部と前記高電圧部の電力が供給される電気負荷(10)との電気的な接続状態を切り替える切替手段(15)と、を備え、Switching means (15) for switching an electrical connection state between the high voltage unit and an electric load (10) to which power of the high voltage unit is supplied,
前記判定値設定手段は、前記切替手段がオフの際に前記波高値算出手段により算出した前記交流信号の波高値を用いて、前記地絡判定値を設定し、The determination value setting means sets the ground fault determination value using the peak value of the AC signal calculated by the peak value calculation means when the switching means is off,
前記地絡判定手段は、前記波高値算出手段で算出した前記波高値が前記地絡判定値以下となる場合に、前記切替手段を開閉させ、その開閉により、前記波高値が変化した場合には地絡であると判定し、前記波高値が変化しなかった場合には前記切替手段のオン故障であると判定することを特徴とする地絡判定装置。The ground fault determination means opens and closes the switching means when the peak value calculated by the peak value calculation means is less than or equal to the ground fault determination value, and when the peak value changes due to the opening and closing. A ground fault determination device that determines that a ground fault has occurred and determines that the switching means is on failure when the peak value does not change.
前記判定値設定手段は、前記所定条件が成立する都度、前記波高値算出手段により算出した今回の前記波高値とそれ以前の前記波高値とに基づいて前記地絡判定値を今回値に更新するものであり、
前記地絡判定手段は、前記所定条件が成立する都度、前記判定値設定手段により更新される前の前記地絡判定値の前回値を用いて前記地絡判定を実施する請求項1乃至のいずれか1項に記載の地絡判定装置。
The determination value setting unit updates the ground fault determination value to the current value based on the current peak value calculated by the peak value calculating unit and the previous peak value every time the predetermined condition is satisfied. Is,
It said ground fault judging means, wherein each time a predetermined condition is satisfied, of claims 1 to 4 implementing the grounding determined using the last value of the ground絡判value before being updated by the determination value setting means The ground fault determination apparatus of any one of Claims.
前記高電圧部は、車両に搭載されたバッテリ(11)であり、
前記判定値設定手段は、前記車両の動作開始時及び動作終了時の少なくともいずれかであることを前記所定条件として、前記地絡判定値の設定を実施する請求項1乃至のいずれか1項に記載の地絡判定装置。
The high voltage unit is a battery (11) mounted on a vehicle,
The determination value setting means, that at least one of the operation start and operation end of the vehicle as the predetermined condition, any one of claims 1 to 5 performs the setting of the ground絡判value The ground fault determination apparatus as described in.
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