JP2013140074A - Electric leak detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric leak detecting device that can detect any electric leak appropriately without being affected by deterioration of elements constituting the electric leak detecting device or by an ambient temperature.SOLUTION: An electric leak determining circuit 17 cuts a second end of a resistor 11 off from a high voltage battery B1 by controlling a first change-over switch 13, connects a second end of an impedance circuit to a reference impedance circuit 14 by controlling a second change-over switch 15, detects a peak value of an AC signal at the second end of the resistor 11, and uses it as a reference peak value. After that, the second end of the resistor 11 is cut off from the reference impedance circuit 14 by controlling the second change-over switch 15, the second end of the impedance circuit is connected to the high voltage battery B1 by controlling the first change-over switch 13, and the presence or absence of electric leak is determined on the basis of the peak value of the AC signal at the second end of the register 11 and the reference peak value. The reference peak value varies with deterioration of elements constituting an electric leak detecting device 1 or an ambient temperature. Therefore, any electric leak can be detected appropriately without being affected by deterioration of the elements constituting the electric leak detecting device 1 or by the ambient temperature.

Description

  The present invention relates to a leakage detection device that detects the presence or absence of leakage.

  Conventionally, there is a ground fault detection circuit disclosed in Patent Document 1, for example, as a leakage detection device that detects the presence or absence of leakage.

  The ground fault detection circuit includes a microcomputer, an oscillation output unit, an output impedance element, and a coupling capacitor. The microcomputer generates a pulse voltage having a predetermined frequency. The oscillation output unit amplifies and outputs the pulse voltage output from the microcomputer. The pulse voltage output from the oscillation output unit is applied to the high voltage battery via the output impedance element and the coupling capacitor. The high voltage battery has an insulation impedance composed of a ground insulation resistance and a ground parasitic capacitance. Therefore, a pulse voltage divided by the insulation impedance of the output impedance element and the high voltage battery is generated at the connection point between the output impedance element and the coupling capacitor. The peak value of the pulse voltage generated at the connection point between the output impedance element and the coupling capacitor varies depending on the insulation state of the high voltage battery. The microcomputer determines the presence or absence of a ground fault in the high-voltage battery based on the peak value of the pulse voltage generated at the connection point between the output impedance element and the coupling capacitor.

JP 2003-274504 A

  By the way, the peak value of the pulse voltage generated at the connection point between the output impedance element and the coupling capacitor is changed not only by the insulation state of the high voltage battery but also by the deterioration of the elements constituting the ground fault detection circuit and the ambient temperature. Therefore, depending on the deterioration state of the elements that make up the ground fault detection circuit and the ambient temperature, it is judged that there is a ground fault despite the ground fault, or there is a ground fault despite the fact that there is no ground fault. There is a possibility that an erroneous detection such as judging that the ground fault has occurred and the ground fault cannot be detected properly.

  This invention is made in view of such a situation, and provides the leakage detection apparatus which can detect a leakage appropriately, without being influenced by degradation of the element which comprises a leakage detection apparatus, or ambient temperature. With the goal.

  Therefore, as a result of intensive research and trial and error to solve this problem, the present inventors have provided a reference impedance circuit, detected the peak value of the AC signal when the reference impedance circuit is connected, and the reference peak value As a result of the determination based on the reference peak value, it has been found that leakage can be appropriately detected without being affected by deterioration of elements constituting the leakage detection device or ambient temperature, and the present invention has been completed.

  That is, the leakage detection device according to claim 1 is configured such that an AC signal output circuit that outputs an AC signal, an impedance circuit that is set to a predetermined impedance, one end connected to the output end of the AC signal output circuit, and one end Leakage determination that determines the presence or absence of a leak in the leakage detection target based on the coupling capacitor connected to the leakage detection target at the other end of the impedance circuit and the peak value of the AC signal at the other end of the impedance circuit A first switching circuit for connecting or disconnecting the other end of the impedance circuit to the leakage detection target, a reference impedance circuit set to a reference impedance, and an impedance circuit The second switching circuit that connects or disconnects the other end of the circuit to the reference impedance circuit The leakage determination circuit controls the first switching circuit to disconnect the other end of the impedance circuit from the leakage detection target, and controls the second switching circuit to connect the other end of the impedance circuit to the reference impedance circuit. To the reference peak value by detecting the peak value of the AC signal at the other end of the impedance circuit, and then controlling the second switching circuit to disconnect the other end of the impedance circuit from the reference impedance circuit, and Control the switching circuit to connect the other end of the impedance circuit to the leakage detection target, and determine whether the leakage detection target has a leakage based on the peak value of the AC signal at the other end of the impedance circuit and the detected reference peak value It is characterized by.

  The peak value of the AC signal at the other end of the impedance circuit varies depending not only on the insulation state of the leakage detection target but also on the deterioration of the elements constituting the leakage detection device and the ambient temperature. Therefore, when the presence or absence of leakage is determined based on the peak value of the AC signal at the other end of the impedance circuit, depending on the deterioration state of the elements constituting the leakage detection device and the ambient temperature, the leakage may occur. There is a possibility that an erroneous detection may occur that it is determined that there is no leakage, or that it is determined that there is a leakage even though there is no leakage, and the leakage cannot be detected properly. However, according to this configuration, the leakage determination circuit connects the reference impedance circuit to the other end of the impedance circuit, detects the peak value of the AC signal at the other end of the impedance circuit, and sets it as the reference peak value. The reference peak value varies depending on deterioration of elements constituting the leakage detection device and ambient temperature. Therefore, by determining based on the peak value of the AC signal at the other end of the impedance circuit and the reference peak value, it is possible to suppress the deterioration of the elements constituting the leakage detection device and the influence of the ambient temperature, and to determine the presence or absence of leakage. it can. Therefore, it is possible to appropriately detect a leakage without being affected by these.

  In the leakage detection device according to claim 2, the reference impedance circuit is set to a reference impedance when determining the presence or absence of leakage, and the leakage determination circuit detects the peak value of the AC signal at the other end of the impedance circuit and the detection. It is characterized in that the presence / absence of leakage of the leakage detection target is determined based on the comparison result of the reference wave height values. According to this configuration, the detected reference peak value becomes a reference when determining the presence or absence of leakage, which changes according to the deterioration state of the elements constituting the leakage detection device and the ambient temperature. Therefore, by making a determination based on the comparison result between the peak value of the AC signal at the other end of the impedance circuit and the detected reference peak value, the leakage can be prevented without being affected by the deterioration of the elements constituting the leakage detection device or the ambient temperature. It can be detected reliably.

  The leakage detection device according to claim 3, wherein the leakage determination circuit is a reference for determining the presence or absence of leakage, a leakage radio wave peak value that is a peak value of an AC signal at the other end of the impedance circuit, and a reference in a predetermined condition The peak value is set in advance, and the leaked radio wave peak value is corrected based on the reference peak value in the predetermined condition and the detected reference peak value, and the peak value of the AC signal at the other end of the impedance circuit and the corrected leaked wave peak value It is characterized by determining the presence or absence of electric leakage. According to this configuration, the detected reference peak value varies depending on the deterioration state of the elements constituting the leakage detection device and the ambient temperature. For this reason, the leaked radio wave peak value can be corrected according to the deterioration state of the elements constituting the leakage detection device and the ambient temperature condition based on the reference peak value and the detected reference peak value under a predetermined condition set in advance. Therefore, by making a determination based on the peak value of the AC signal at the other end of the impedance circuit and the corrected leaked radio wave peak value, leakage can be reliably detected without being affected by the deterioration of the elements constituting the leak detection device or the ambient temperature. can do.

  In the leakage detection device according to claim 4, the first switching circuit is provided between the coupling capacitor and the leakage detection target, and the second switching circuit is connected between the coupling capacitor and the first switching circuit. It is characterized by being. According to this configuration, it is possible to detect the reference peak value considering the impedance of the coupling capacitor. As a result, the detection accuracy of leakage can be improved.

  According to a fifth aspect of the present invention, the first switching circuit is provided between the impedance circuit and the coupling capacitor, and the second switching circuit is connected between the impedance circuit and the first switching circuit. It is characterized by. According to this configuration, the first switching circuit, the reference impedance circuit, and the second switching circuit are galvanically isolated from the leakage detection target by the coupling capacitor. For this reason, even when the leakage detection target voltage is a high voltage, the withstand voltages of the first switching circuit, the reference impedance circuit, and the second switching circuit can be suppressed. Therefore, the cost can be suppressed.

  The leakage detection device according to claim 6 is characterized in that the reference impedance circuit is set in consideration of the impedance of the coupling capacitor. According to this configuration, it is possible to improve the leakage detection accuracy compared to the case where the impedance of the coupling capacitor is not taken into consideration.

  The leakage detection device according to claim 7 is characterized in that the leakage detection target is mounted on the vehicle and insulated from the vehicle body. According to this configuration, it is possible to appropriately detect the leakage of the leakage detection target that is mounted on the vehicle and insulated from the vehicle body without being affected by deterioration of the elements constituting the leakage detection device or the ambient temperature.

It is a circuit diagram of the earth-leakage detection apparatus in 1st Embodiment. It is a circuit diagram for demonstrating the detection operation | movement of the reference peak value for earth leakage determination of the earth leakage detection apparatus shown in FIG. It is a circuit diagram for demonstrating the leak determination operation | movement of the leak detection apparatus shown in FIG. It is a circuit diagram of the earth-leakage detection apparatus in 4th Embodiment. It is explanatory drawing for demonstrating the impedance of a reference | standard impedance circuit. It is a circuit diagram of the earth-leakage detection apparatus in 5th Embodiment. It is a circuit diagram for demonstrating the detection operation | movement of the reference peak value for earth leakage determination of the earth leakage detection apparatus shown in FIG. It is a circuit diagram for demonstrating the detection operation | movement of the reference peak value for earth leakage cancellation of the earth leakage detection apparatus shown in FIG. It is a circuit diagram for demonstrating the leak determination operation | movement of the leak detection apparatus shown in FIG. It is a circuit diagram of the earth-leakage detection apparatus in 6th Embodiment.

Next, the present invention will be described in more detail with reference to embodiments. In this embodiment, the example which applied the earth-leakage detection apparatus which concerns on this invention to the earth-leakage detection apparatus which detects the earth-leakage of the high voltage battery mounted in the hybrid vehicle is shown.
(First embodiment)
Next, the leakage detection device of the first embodiment will be described. First, the configuration of the leakage detection device of the first embodiment will be described with reference to FIG. Here, FIG. 1 is a circuit diagram of the leakage detecting device in the first embodiment.

  A leakage detection device 1 (leakage detection device) shown in FIG. 1 is a device that detects leakage of a high-voltage battery B1 (leakage detection target) mounted in a hybrid vehicle. Here, the high voltage battery B1 is a power source that supplies electric power to a motor for generating driving force in a hybrid vehicle. The high voltage battery B1 is insulated from the vehicle body. Therefore, an insulation resistance Rg and a stray capacitance Cg exist between the high voltage battery B1 and the vehicle body. One end of the insulation resistance Rg is connected to the high voltage battery B1, and the other end is grounded to the vehicle body. One end and the other end of the stray capacitance Cg are connected to one end and the other end of the insulation resistance Rg, respectively. The leakage detection device 1 includes an AC signal output circuit 10, a resistor 11 (impedance circuit), a coupling capacitor 12, a first changeover switch 13 (first changeover circuit), a reference impedance circuit 14, and a second changeover switch. 15 (second switching circuit), a filter circuit 16, and a leakage determination circuit 17.

  The AC signal output circuit 10 is a circuit that outputs an AC signal having a predetermined frequency. Specifically, it is a circuit for outputting a rectangular wave pulse signal. The output terminal of the AC signal output circuit 10 is connected to the resistor 11.

  The resistor 11 is an element that is set to a predetermined resistance value (predetermined impedance) and divides an AC signal. One end of the resistor 110 is connected to the output end of the AC signal output circuit 10, and the other end is connected to the coupling capacitor 12 and the filter circuit 16.

  The coupling capacitor 12 is an element for blocking a direct current component and insulating one end side and the other end side in a direct current manner. One end of the coupling capacitor 12 is connected to the other end of the resistor 110, and the other end is connected to the first changeover switch 13 and the second changeover switch 15.

  The first changeover switch 13 is an element for connecting the other end of the resistor 11 to the high voltage battery B1 or disconnecting from the high voltage battery B1. The first changeover switch 13 is provided between the coupling capacitor 12 and the high voltage battery B1. One end of the first changeover switch 13 is connected to the other end of the coupling capacitor 12, and the other end is connected to the high voltage battery B1. Further, the control end is connected to the leakage determination circuit 17.

  The reference impedance circuit 14 is a circuit set to an impedance that serves as a reference when determining that there is a leakage. The reference impedance circuit 14 includes a resistor 140 and a capacitor 141. One end of the resistor 140 is connected to the second changeover switch 15 and the other end is grounded to the vehicle body. One end and the other end of the capacitor 141 are connected to one end and the other end of the resistor 140, respectively. Here, the impedance of the reference impedance circuit 14 is set to a leakage determination impedance which is a combined impedance of the insulation resistance Rg and the stray capacitance Cg when it is determined that there is a leakage at normal temperature.

  The second changeover switch 15 is an element for connecting or disconnecting the other end of the resistor 11 to the reference impedance circuit 14. The second changeover switch 15 is connected between the coupling capacitor 12 and the first changeover switch 13. One end of the second changeover switch 15 is connected to the other end of the coupling capacitor 12, and the other end is connected to one end of the resistor 140 and the capacitor 141. Further, the control end is connected to the leakage determination circuit 17.

  The filter circuit 16 is a circuit for removing a high-frequency component contained in the AC signal at the other end of the resistor 11. The filter circuit 16 includes a resistor 160 and a capacitor 161. One end of the resistor 160 is connected to the other end of the resistor 11, and the other end is connected to the leakage determination circuit 17. One end of the capacitor 161 is connected to the other end of the resistor 160, and the other end is grounded to the vehicle body.

  The leakage determination circuit 17 is a circuit that determines whether or not the high-voltage battery B1 has a leakage based on the peak value of the AC signal at the other end of the resistor 11 from which the high-frequency component has been removed by the filter circuit 16. Specifically, prior to the determination of leakage, the first switch 13 is controlled to disconnect the other end of the resistor 11 from the high-voltage battery B1, and the second switch 15 is controlled to control the other end of the resistor 11. Is connected to the reference impedance circuit 14, and the peak value of the AC signal at the other end of the resistor 11 is detected and used as a reference peak value for determining leakage. Thereafter, the second changeover switch 15 is controlled to disconnect the other end of the resistor 11 from the reference impedance circuit 14, and the first changeover switch 13 is controlled to connect the other end of the resistor 11 to the high voltage battery B1. 11 is determined based on the result of comparison between the peak value of the AC signal at the other end of 11 and the detected reference peak value for leakage detection. The input terminal of the leakage detection circuit 17 is connected to the other end of the resistor 160 and one end of the capacitor 161. The output ends are connected to the control end of the first changeover switch 13 and the control end of the second changeover switch 15, respectively.

  Next, the operation of the leakage detection device will be described with reference to FIGS. Here, FIG. 2 is a circuit diagram for explaining the detection operation of the reference peak value for leak detection of the leak detection apparatus shown in FIG. FIG. 3 is a circuit diagram for explaining a leakage determination operation of the leakage detection apparatus shown in FIG.

  The AC signal output circuit 10 shown in FIG. 1 outputs a rectangular wave pulse signal having a predetermined frequency.

  Prior to determining the leakage of the high voltage battery B1, the leakage determination circuit 17 controls the first changeover switch 13 to disconnect the other end of the resistor 11 from the high voltage battery B1, as shown in FIG. 2 controls the changeover switch 15 to connect the other end of the resistor 11 to the reference impedance circuit 14 via the coupling capacitor 12, and detects the peak value of the AC signal at the other end of the resistor 11 to determine the reference for determining the leakage. The peak value.

  Thereafter, as shown in FIG. 3, the leakage determination circuit 17 controls the second changeover switch 15 to disconnect the other end of the resistor 11 from the reference impedance circuit 14, and also controls the first changeover switch 13 to control the resistance 11 Is connected to the high voltage battery B1 through the coupling capacitor 12, and the high voltage battery is based on the comparison result between the peak value of the AC signal at the other end of the resistor 11 and the detected reference peak value for leakage detection. The presence / absence of leakage of B1 is determined. Specifically, when the peak value of the AC signal at the other end of the resistor 11 is equal to or less than the detected reference peak value for leakage detection, the insulation impedance composed of the insulation resistance Rg and the stray capacitance Cg decreases and the leakage occurs. judge.

  Next, the effect will be described. The peak value of the AC signal at the other end of the resistor 11 varies depending not only on the insulation state of the high-voltage battery B1, but also on the deterioration of the elements constituting the leakage detection device 1 and the ambient temperature. Therefore, when the presence / absence of leakage is determined based on the peak value of the AC signal at the other end of the resistor 11, the leakage is detected depending on the deterioration state of the elements constituting the leakage detection device 1 and the ambient temperature. There is a possibility that an erroneous detection may occur that it is determined that there is no leakage, or that it is determined that there is a leakage even though there is no leakage, and the leakage cannot be detected properly. However, according to the first embodiment, the leakage determination circuit 17 connects the reference impedance circuit 14 to the other end of the resistor 11 and detects the peak value of the AC signal at the other end of the resistor 11 to obtain the reference peak value. . The reference peak value varies depending on the deterioration of the elements constituting the leakage detection device 1 and the ambient temperature. Therefore, by determining based on the peak value of the AC signal at the other end of the resistor 11 and the reference peak value, it is possible to suppress the deterioration of the elements constituting the leakage detection device 1 and the influence of the ambient temperature and determine the presence or absence of leakage. Can do. Therefore, the leakage of the high-voltage battery B1 mounted on the hybrid vehicle and insulated from the vehicle body can be appropriately detected without being affected by deterioration of the elements constituting the leakage detection device 1 or the ambient temperature.

  Further, according to the first embodiment, the reference impedance circuit 14 is set to an impedance that serves as a reference when determining the presence or absence of leakage. Therefore, the detected reference peak value is a reference for determining the presence or absence of leakage, which changes according to the deterioration state of the elements constituting the leakage detection device 1 and the ambient temperature. Therefore, by making a determination based on the comparison result between the peak value of the AC signal at the other end of the resistor 11 and the detected reference peak value, the leakage current is not affected by the deterioration of the elements constituting the leakage detection device 1 or the ambient temperature. Can be reliably detected.

  Furthermore, according to the first embodiment, the first change-over switch 13 is provided between the coupling capacitor 12 and the high-voltage battery B1, and the second change-over switch 15 is provided between the coupling capacitor 12 and the first change-over switch 13. Connected between. Therefore, the reference peak value considering the impedance of the coupling capacitor 12 can be detected. Therefore, the detection accuracy of electric leakage can be improved.

(Second Embodiment)
Next, the leakage detection device of the second embodiment will be described. In the leakage detection device of the second embodiment, the leakage detection device of the first embodiment determines leakage based on the comparison result between the peak value of the AC signal at the other end of the resistor and the detected reference peak value. , The leakage determination peak value set in advance is corrected based on the detected reference peak value, and the leakage is determined based on the corrected peak value of the AC signal at the other end of the resistor and the corrected leakage determination peak value. It is. The leakage detection device of the second embodiment has the same configuration as the leakage detection device of the first embodiment except for the impedance of the reference impedance circuit and the operation of the leakage determination circuit. Therefore, the configuration and operation of the leakage detection apparatus of the second embodiment will be described with reference to FIG.

  The impedance of the reference impedance circuit 14 shown in FIG. 1 is set to a predetermined impedance at room temperature. Unlike the first embodiment, it is not necessary to set the leakage determination impedance.

  In the leakage determination circuit 17, a leakage determination peak value (leakage radio wave peak value) that is a peak value of the AC signal at the other end of the resistor 11 is set in advance as a reference when determining that there is a leakage. Further, a reference peak value at normal temperature (predetermined condition) is set in advance.

  Prior to the determination of leakage, the leakage determination circuit 17 controls the first changeover switch 13 to disconnect the other end of the resistor 11 from the high-voltage battery B1, and controls the second changeover switch 15 to control the other of the resistor 11. One end is connected to the reference impedance circuit 14 via the coupling capacitor 12, and the peak value of the AC signal at the other end of the resistor 11 is detected and set as the reference peak value. Then, the leakage determination peak value is corrected based on the preset reference peak value at normal temperature and the detected reference peak value. Specifically, the leakage determination peak value is corrected based on a deviation or change rate between a preset reference peak value at normal temperature and the detected reference peak value.

  Thereafter, the leakage determination circuit 17 controls the second changeover switch 15 to disconnect the other end of the resistor 11 from the reference impedance circuit 14 and controls the first changeover switch 13 to couple the other end of the resistor 11 to the coupling. It is connected to the high voltage battery B1 via the capacitor 12, and the presence or absence of leakage of the high voltage battery B1 is determined based on the comparison result between the peak value of the AC signal at the other end of the resistor 11 and the corrected leakage current peak value. Specifically, when the peak value of the AC signal at the other end of the resistor 11 is equal to or less than the corrected leakage current peak value, it is determined that the insulation impedance composed of the insulation resistance Rg and the stray capacitance Cg is reduced and the leakage occurs.

  Next, the effect will be described. According to the second embodiment, the leakage determination circuit 17 includes a leakage determination peak value that is a peak value of the AC signal at the other end of the resistor 11 and a reference at room temperature, which is a reference when determining that there is a leakage. The peak value is set in advance. The detected reference peak value varies depending on the deterioration state of the elements constituting the leakage detection device 1 and the ambient temperature. Therefore, the leakage determination peak value can be corrected according to the deterioration state of the elements constituting the leakage detection device 1 and the ambient temperature state, based on the preset reference peak value at normal temperature and the detected reference peak value. Therefore, by making a determination based on the peak value of the AC signal at the other end of the resistor 11 and the corrected leakage peak value, the leakage can be reliably prevented without being affected by the deterioration of the elements constituting the leakage detection device 1 or the ambient temperature. Can be detected.

(Third embodiment)
Next, the leakage detection device of the third embodiment will be described. In the leakage detection device of the third embodiment, the leakage detection device of the second embodiment corrects the preset leakage determination peak value and determines the leakage based on the corrected leakage determination peak value. In addition to the leakage determination peak value, the leakage cancellation peak value is set in advance, and the preset leakage determination peak value and leakage cancellation peak value are corrected, and based on the corrected leakage determination peak value and leakage cancellation peak value This is to determine the electric leakage. The leakage detection device of the third embodiment has the same configuration as the leakage detection device of the second embodiment except for the operation of the leakage determination circuit. Therefore, as in the case of the second embodiment, the configuration, operation, and effect of the leakage detecting device of the third embodiment will be described with reference to FIG.

  In the leakage determination circuit 17, a leakage determination peak value (leakage radio wave peak value) that is a peak value of the AC signal at the other end of the resistor 11 is set in advance as a reference when determining that there is a leakage. In addition, an earth leakage cancellation peak value (leakage signal peak value) that is larger than the leak determination peak value that is the peak value of the AC signal at the other end of the resistor 11 is set in advance as a reference for determining that there is no leakage. . Further, a reference peak value at normal temperature (predetermined condition) is set in advance.

  Prior to the determination of leakage, the leakage determination circuit 17 controls the first changeover switch 13 to disconnect the other end of the resistor 11 from the high-voltage battery B1, and controls the second changeover switch 15 to control the other of the resistor 11. One end is connected to the reference impedance circuit 14 via the coupling capacitor 12, and the peak value of the AC signal at the other end of the resistor 11 is detected and set as the reference peak value. Then, based on the preset reference peak value at normal temperature and the detected reference peak value, the leakage determination peak value and the leakage cancellation peak value are corrected. Specifically, the leakage determination peak value and the leakage cancellation peak value are corrected based on a deviation or change rate between a preset reference peak value at normal temperature and the detected reference peak value.

  Thereafter, the leakage determination circuit 17 controls the second changeover switch 15 to disconnect the other end of the resistor 11 from the reference impedance circuit 14 and controls the first changeover switch 13 to couple the other end of the resistor 11 to the coupling. The high voltage battery B1 is connected to the high voltage battery B1 via the capacitor 12. Based on the comparison result between the peak value of the AC signal at the other end of the resistor 11 and the corrected leaked radio wave peak value, the presence or absence of leakage of the high voltage battery B1 is determined. Specifically, when the peak value of the AC signal at the other end of the resistor 11 is equal to or less than the corrected leakage current peak value, it is determined that the insulation impedance composed of the insulation resistance Rg and the stray capacitance Cg is reduced and the leakage occurs. Further, when the peak value of the AC signal at the other end of the resistor 11 is equal to or higher than the corrected leakage current peak value, it is determined that the current leakage state has returned to the normal state. Thereby, the effect similar to 2nd Embodiment can be acquired.

(Fourth embodiment)
Next, the leakage detection device of the fourth embodiment will be described. In the leakage detection device of the fourth embodiment, the leakage detection device of the first embodiment has the first changeover switch, the reference impedance circuit, and the second changeover switch on the other end side of the coupling capacitor, that is, on the high voltage battery side. On the other hand, a first changeover switch, a reference impedance circuit, and a second changeover switch are provided on one end side of the coupling capacitor, that is, on the anti-high voltage battery side.

  First, with reference to FIG.4 and FIG.5, the structure of the earth-leakage detection apparatus of 4th Embodiment is demonstrated. Here, FIG. 4 is a circuit diagram of the leakage detecting device in the fourth embodiment. FIG. 5 is an explanatory diagram for explaining the impedance of the reference impedance circuit.

  4 includes an AC signal output circuit 40, a resistor 41 (impedance circuit), a coupling capacitor 42, a first changeover switch 43 (first changeover circuit), a reference impedance circuit 44, A second changeover switch 45 (second changeover circuit), a filter circuit 46, and a leakage determination circuit 47 are provided.

  The AC signal output circuit 40, the resistor 41, the filter circuit 46, and the leakage determination circuit 47 have the same configuration as the AC signal output circuit 10, the resistor 11, the filter circuit 16, and the leakage determination circuit 17 of the first embodiment.

  One end of the first changeover switch 43 is connected to the other end of the resistor 41, and the other end is connected to the coupling capacitor 42. Further, the control end is connected to the leakage determination circuit 47. One end of the coupling capacitor 42 is connected to the other end of the first changeover switch 43, and the other end is connected to the high voltage battery B4. That is, the first changeover switch 43 is provided between the resistor 41 and the coupling capacitor 42.

  One end of the second changeover switch 45 is connected to the other end of the resistor 41, and the other end is connected to one end of the resistor 440 and the capacitor 441. That is, the second changeover switch 45 is connected between the resistor 41 and the first changeover switch 43.

  The impedance of the reference impedance circuit 44 is set to a leakage determination impedance that is a combined impedance of the insulation resistance Rg and the stray capacitance Cg at the time of determining that there is a leakage at room temperature in consideration of the impedance of the coupling capacitor 42. ing. Specifically, as shown in FIG. 5, the resistance value of the resistor 440 and the capacitor are set so that the impedance of the reference impedance circuit 44 is equal to the impedance of the circuit including the coupling capacitor 42, the insulation resistance Rg, and the stray capacitance Cg. A capacity of 441 is set. At this time, the impedance of the coupling capacitor 42 may be set to be included on the resistor 440 side, or may be set to be included on the capacitor 441 side.

  Since the operation is the same as in the first embodiment, a description thereof will be omitted.

  Next, the effect will be described. According to the fourth embodiment, the first changeover switch 43 is provided between the resistor 41 and the coupling capacitor 42, and the second changeover switch 45 is connected between the resistor 41 and the first changeover switch 43. . Therefore, the first changeover switch 43, the reference impedance circuit 44, and the second changeover switch 45 are galvanically isolated from the high voltage battery B4 by the coupling capacitor. Therefore, the withstand voltages of the first changeover switch 43, the reference impedance circuit 44, and the second changeover switch 45 can be suppressed. Therefore, the cost can be suppressed.

  Further, according to the fourth embodiment, the reference impedance circuit 44 is set in consideration of the impedance of the coupling capacitor 42. Therefore, compared with the case where the impedance of the coupling capacitor 42 is not taken into account, the leakage detection accuracy can be improved.

(Fifth embodiment)
Next, a leakage detection device according to a fifth embodiment will be described. In the leakage detection device of the fifth embodiment, the leakage detection device of the first embodiment determines leakage based on the detected reference peak value for leakage detection. A reference wave height value for leakage cancellation is detected, and the presence or absence of leakage is determined based on the detected reference wave height value for leakage detection and the reference wave height value for leakage cancellation.

  First, the configuration of the leakage detection apparatus of the fifth embodiment will be described with reference to FIG. Here, FIG. 6 is a circuit diagram of the leakage detecting device in the fifth embodiment.

  6 includes an AC signal output circuit 50, a resistor 51 (impedance circuit), a coupling capacitor 52, a first switch 53 (first switch circuit), and a reference impedance circuit 54 (reference). Impedance circuit), second switching switch 55 (second switching circuit), reference impedance circuit 56 (reference impedance circuit), third switching switch 57 (second switching circuit), filter circuit 58, and leakage determination circuit. 59. The AC signal output circuit 50, the resistor 51, the coupling capacitor 52, the first changeover switch 53, the reference impedance circuit 54, the second changeover switch 55, and the filter circuit 58 are the AC signal output circuit 10, the resistor 11, and the first embodiment. The coupling capacitor 12, the first changeover switch 13, the reference impedance circuit 14, the second changeover switch 15 and the filter circuit 16 have the same configuration.

  The reference impedance circuit 56 is a circuit set to an impedance that serves as a reference when determining that there is no leakage. The reference impedance circuit 56 includes a resistor 560 and a capacitor 561. One end of the resistor 560 is connected to the third changeover switch 57, and the other end is grounded to the vehicle body. One end and the other end of the capacitor 561 are connected to one end and the other end of the resistor 560, respectively. Here, the impedance of the reference impedance circuit 56 is set to a leakage cancellation impedance larger than the leakage determination impedance, which is a combined impedance of the insulation resistance Rg and the stray capacitance Cg when determining that there is no leakage at room temperature.

  The third changeover switch 57 is an element for connecting or disconnecting the other end of the resistor 51 to the reference impedance circuit 56. The third changeover switch 57 is connected between the coupling capacitor 52 and the first changeover switch 53. One end of the third changeover switch 57 is connected to the other end of the coupling capacitor 52, and the other end is connected to one end of the resistor 560 and the capacitor 561. Further, the control end is connected to a leakage determination circuit 59.

  The leakage determination circuit 59 is a circuit that determines the presence or absence of leakage of the high-voltage battery B5 based on the peak value of the AC signal at the other end of the resistor 51 from which the high-frequency component has been removed by the filter circuit 58. Specifically, prior to the determination of leakage, the first changeover switch 53 and the third changeover switch 57 are controlled to disconnect the other end of the resistor 51 from the high voltage battery B5 and the reference impedance circuit 56, and the second changeover is performed. The switch 55 is controlled so that the other end of the resistor 51 is connected to the reference impedance circuit 54 through the coupling capacitor 52, and the peak value of the AC signal at the other end of the resistor 51 is detected to determine the reference peak value for determining the leakage. And

  Thereafter, the leakage determination circuit 59 controls the first changeover switch 53 and the second changeover switch 55 to disconnect the other end of the resistor 51 from the high voltage battery B5 and the reference impedance circuit 54, and also controls the third changeover switch 57. Then, the other end of the resistor 51 is connected to the reference impedance circuit 56 via the coupling capacitor 52, and the peak value of the AC signal at the other end of the resistor 51 is detected and used as the reference peak value for releasing the leakage.

  Then, the leakage determination circuit 59 controls the second changeover switch 55 and the third changeover switch 57 to disconnect the other end of the resistor 51 from the reference impedance circuits 54 and 56, and also controls the first changeover switch 53 to change the resistance. The other end of 51 is connected to the high voltage battery B5 via the coupling capacitor 52, and the comparison result between the peak value of the AC signal at the other end of the resistor 51 and the detected reference peak value for leakage detection and leakage cancellation Based on the above, the presence / absence of leakage of the high voltage battery B5 is determined.

  The input terminal of the leakage detection circuit 59 is connected to the other end of the resistor 580 and one end of the capacitor 581. The output ends are connected to the control ends of the first changeover switch 53, the second changeover switch 55, and the third changeover switch 57, respectively.

  Next, the operation and effect of the leakage detection device will be described with reference to FIGS. Here, FIG. 7 is a circuit diagram for explaining the detection operation of the reference peak value for leak detection of the leak detection apparatus shown in FIG. FIG. 8 is a circuit diagram for explaining the detection operation of the reference peak value for canceling leakage of the leakage detecting device shown in FIG. FIG. 9 is a circuit diagram for explaining a leakage determination operation of the leakage detection apparatus shown in FIG.

  The AC signal output circuit 50 shown in FIG. 6 outputs a rectangular wave pulse signal having a predetermined frequency.

  Prior to determining leakage of the high voltage battery B5, the leakage determination circuit 59 controls the first changeover switch 53 and the third changeover switch 57 to connect the other end of the resistor 51 to the high voltage battery B5 as shown in FIG. Disconnecting from the reference impedance circuit 56 and controlling the second changeover switch 55 to connect the other end of the resistor 51 to the reference impedance circuit 54 via the coupling capacitor 52, and to connect the AC signal at the other end of the resistor 51. The peak value is detected and used as a reference peak value for leakage detection.

  Thereafter, as shown in FIG. 8, the leakage determination circuit 59 controls the first changeover switch 53 and the second changeover switch 55 to disconnect the other end of the resistor 51 from the high voltage battery B5 and the reference impedance circuit 54, and The third changeover switch 57 is controlled so that the other end of the resistor 51 is connected to the reference impedance circuit 56 via the coupling capacitor 52, and the peak value of the AC signal at the other end of the resistor 51 is detected to cancel the leakage. The reference wave height is assumed.

  Then, as shown in FIG. 9, the leakage determination circuit 59 controls the second change-over switch 55 and the third change-over switch 57 to disconnect the other end of the resistor 51 from the reference impedance circuits 54 and 56, and the first changeover The switch 53 is controlled so that the other end of the resistor 51 is connected to the high voltage battery B5 via the coupling capacitor 52, and the peak value of the AC signal at the other end of the resistor 51 is detected and detected for leakage detection and leakage cancellation. Based on the comparison result with the reference peak value, the presence / absence of leakage of the high voltage battery B5 is determined. Specifically, when the peak value of the AC signal at the other end of the resistor 51 is equal to or less than the reference peak value for leakage detection, it is determined that the insulation impedance composed of the insulation resistance Rg and the stray capacitance Cg is reduced and the leakage occurs. . Further, when the peak value of the AC signal at the other end of the resistor 51 becomes equal to or higher than the reference peak value for canceling the leakage, it is determined that the leakage state is restored to the normal state. Thereby, the effect similar to 1st Embodiment can be acquired.

(Sixth embodiment)
Next, a leakage detection apparatus according to the sixth embodiment will be described. The leakage detection device according to the sixth embodiment is the same as the leakage detection device according to the fifth embodiment except that the first changeover switch, the reference impedance circuit, the second changeover switch, and the third changeover switch are connected to the other end of the coupling capacitor, that is, the high voltage battery. In contrast to the changeover switch, the first changeover switch, the reference impedance circuit, the second changeover switch, and the third changeover switch are provided on one end side of the coupling capacitor, that is, on the anti-high voltage battery side.

  First, with reference to FIG. 10, the structure, operation | movement, and effect of the leak detection apparatus of 6th Embodiment are demonstrated. Here, FIG. 10 is a circuit diagram of the leakage detecting device in the sixth embodiment.

  10 includes an AC signal output circuit 60, a resistor 61 (impedance circuit), a coupling capacitor 62, a first switch 63 (first switch circuit), and a reference impedance circuit 64 (reference). Impedance circuit), second switching switch 65 (second switching circuit), reference impedance circuit 66 (reference impedance circuit), third switching switch 67 (second switching circuit), filter circuit 68, and leakage determination circuit. 69. The AC signal output circuit 60, the resistor 61, the filter circuit 68, and the leakage determination circuit 69 have the same configuration as the AC signal output circuit 50, the resistor 51, the filter circuit 58, and the leakage determination circuit 59 of the fifth embodiment.

  One end of the first changeover switch 63 is connected to the other end of the resistor 61, and the other end is connected to the coupling capacitor 62. Further, the control end is connected to a leakage determination circuit 69. One end of the coupling capacitor 62 is connected to the other end of the first changeover switch 63, and the other end is connected to the high voltage battery B6. That is, the first changeover switch 63 is provided between the resistor 61 and the coupling capacitor 62.

  One end of the second changeover switch 65 is connected to the other end of the resistor 61, and the other end is connected to one end of the resistor 640 and the capacitor 641. One end of the third changeover switch 67 is connected to the other end of the resistor 61, and the other end is connected to one end of the resistor 660 and the capacitor 661. That is, the second changeover switch 65 and the third changeover switch 67 are connected between the resistor 61 and the first changeover switch 63.

  The impedance of the reference impedance circuit 64 is set to a leakage determination impedance that is a combined impedance of the insulation resistance Rg and the stray capacitance Cg at the time of determining that there is a leakage at room temperature in consideration of the impedance of the coupling capacitor 62. ing. Specifically, the resistance value of the resistor 640 and the capacitance of the capacitor 641 are set so that the impedance of the reference impedance circuit 64 is equal to the impedance of the circuit including the coupling capacitor 62, the insulation resistance Rg, and the stray capacitance Cg. Yes. At this time, the impedance of the coupling capacitor 62 may be set to be included on the resistor 640 side, or may be set to be included on the capacitor 641 side.

  The impedance of the reference impedance circuit 66 is set to a leakage canceling impedance that is a combined impedance of the insulation resistance Rg and the stray capacitance Cg when it is determined that there is no leakage at room temperature in consideration of the impedance of the coupling capacitor 62. ing. Specifically, the resistance value of the resistor 660 and the capacitance of the capacitor 661 are set so that the impedance of the reference impedance circuit 66 is equal to the impedance of the circuit including the coupling capacitor 62, the insulation resistance Rg, and the stray capacitance Cg. Yes. At this time, the impedance of the coupling capacitor 62 may be set to be included on the resistor 660 side, or may be set to be included on the capacitor 661 side.

  Since the operation is the same as that of the fifth embodiment, a description thereof will be omitted. Thereby, the effect similar to 4th Embodiment can be acquired.

DESCRIPTION OF SYMBOLS 1, 4-6 ... Electric leakage detection apparatus 10, 40, 50, 60 ... AC signal output circuit 11, 41, 51, 61 ... Resistance (impedance circuit), 12, 42, 52, 62 ... Coupling capacitors, 13, 43, 53, 63 ... First changeover switch (first changeover circuit), 14, 44, 54, 56, 64, 66 ... Reference impedance circuit, 140, 440, 540, 560, 640, 660... Resistor, 141, 441, 541, 641, 661... Capacitor, 15, 45, 55, 65... Second changeover switch (second changeover circuit), 16, 46 58, 68 ... Filter circuit, 160, 460, 580, 680 ... Resistance, 161, 461, 581, 681 ... Capacitor, 17, 47, 59, 69 ... Leakage determination circuit 57, 67 ... third changeover switch (second switching circuit), B1, B4~B6 ··· high voltage battery (electric leakage detected), Rg ... insulation resistance, Cg ... stray capacitance

Claims (7)

An AC signal output circuit for outputting an AC signal;
An impedance circuit set to a predetermined impedance and having one end connected to the output end of the AC signal output circuit;
A coupling capacitor having one end connected to the other end of the impedance circuit and the other end connected to a leakage detection target;
Based on the peak value of the AC signal at the other end of the impedance circuit, a leakage determination circuit that determines the presence or absence of leakage of the leakage detection target;
In the earth leakage detection device comprising
A first switching circuit for connecting or disconnecting the other end of the impedance circuit to the leakage detection target;
A reference impedance circuit set to a reference impedance;
A second switching circuit for connecting or disconnecting the other end of the impedance circuit to the reference impedance circuit;
Have
The leakage determination circuit controls the first switching circuit to disconnect the other end of the impedance circuit from the leakage detection target, and controls the second switching circuit to connect the other end of the impedance circuit to the reference impedance. Connected to a circuit, detects the peak value of the AC signal at the other end of the impedance circuit to be a reference peak value, and then controls the second switching circuit to disconnect the other end of the impedance circuit from the reference impedance circuit And controlling the first switching circuit to connect the other end of the impedance circuit to the leakage detection target, based on the peak value of the AC signal and the detected reference peak value at the other end of the impedance circuit. A leakage detection device that determines the presence or absence of leakage in a leakage detection target. The reference impedance circuit is set to an impedance serving as a reference when determining the presence or absence of leakage,
The leakage detection circuit determines whether or not the leakage detection target has a leakage based on a comparison result between a peak value of an AC signal at the other end of the impedance circuit and the detected reference peak value. The leakage detection device described in 1.   The leakage determination circuit has a leakage wave high value that is a peak value of an AC signal at the other end of the impedance circuit, which is a reference for determining the presence or absence of leakage, and a reference peak value in a predetermined condition set in advance, Correcting the leaked radio wave peak value based on a reference peak value under a predetermined condition and the detected reference peak value, and determining whether there is a leak based on the peak value of the AC signal at the other end of the impedance circuit and the corrected leaked wave peak value. The leakage detection device according to claim 1, wherein the leakage detection device is determined. The first switching circuit is provided between the coupling capacitor and the leakage detection target,
The leakage detection device according to claim 1, wherein the second switching circuit is connected between the coupling capacitor and the first switching circuit. The first switching circuit is provided between the impedance circuit and the coupling capacitor;
The leakage detecting device according to claim 1, wherein the second switching circuit is connected between the impedance circuit and the first switching circuit.   6. The leakage detecting device according to claim 5, wherein the reference impedance circuit is set in consideration of an impedance of the coupling capacitor.   The leakage detection device according to claim 1, wherein the leakage detection target is mounted on a vehicle and insulated from a vehicle body.

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