JP2010025624A - Leakage prevention device for electrical apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an electrical leak caused by submergence, in a high-voltage electrical apparatus. <P>SOLUTION: This leakage prevention device 1 includes a high-voltage circuit part 11 for receiving power supply from a high-voltage power source, a low-voltage circuit part 13 for controlling the high-voltage circuit part 11 by receiving power supply from a low-voltage power source 12 having a lower voltage than the high-voltage power source, and a submergence detection part 32 for detecting submergence. The submergence detection part 32 detects submergence up to a prescribed position which is lower than the lowermost end current-carrying part 34 positioned on the lowermost part of a current-carrying part 33 where a high-voltage current flows in the high-voltage circuit part 11. Further, the leakage prevention device 1 includes a submergence determination circuit 36 for determining submergence based on a signal from the submergence detection part 32, and the submergence determination circuit 36 is connected to the low-voltage circuit part 13 arranged above the lowermost end current-carrying part 34. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a leakage prevention device for electrical equipment that prevents leakage due to water immersion.

High-voltage electric devices such as power converters are subjected to ground insulation processing for reasons such as prevention of electric shock, and are provided with a leakage detection circuit for detecting leakage (see, for example, Patent Document 1).
JP 2007-57490 A

  One of the causes of such electric leakage is that water enters the electric equipment. For this reason, a high-voltage electric device has a waterproof structure, and water does not normally enter.

  However, even an electric device having a waterproof structure may be inundated due to deterioration of the sealing member. If a leakage occurs due to flooding, it may cause a failure of the electrical equipment.

  The present invention has been made in view of the above problems, and an object thereof is to prevent leakage due to water immersion.

  According to the first aspect of the present invention, the high-voltage circuit unit that receives power supply from the high-voltage power source, the low-voltage circuit unit that receives power supply from the low-voltage power source having a lower voltage than the high-voltage power source, and controls the high-voltage circuit unit; A submergence detecting unit for detecting that the submerged portion has flowed to a predetermined position below a lowermost end energizing portion among the energizing portions through which a high-voltage current flows in the circuit unit, and a low pressure disposed above the lowermost end energizing portion. An inundation determination circuit connected to the circuit unit and determining the inundation based on a signal from the inundation detection unit.

  According to the said structure, before water adheres to the energization location of a high voltage circuit part or a low voltage circuit part, flooding can be detected. As a result, it is possible to take measures necessary to prevent leakage before leakage due to flooding occurs.

  According to the second aspect of the present invention, the inundation detecting unit imparts a potential difference between two conductive members facing each other.

  According to the above configuration, the potential difference changes when water is interposed between the conductive members to which the potential difference is applied. By measuring the change in potential of the conductive member, it is possible to detect water intrusion.

  According to the third aspect of the present invention, at least one of the two conductor members facing each other is a pointed end with a tip becoming narrower toward the other.

  According to the said structure, it can prevent that a water droplet adheres to the front-end | tip of an electrically-conductive member, and can prevent misdetection of water immersion by a water droplet.

  According to the invention described in claim 4, it is characterized in that it comprises air blowing means for blowing air to a portion where the distance is minimum between the two conductive members.

  According to the said structure, it can prevent that a water droplet accumulates in the location where distance is the minimum between two electrically-conductive members by ventilation, and can prevent erroneously detecting water immersion by a water droplet.

  According to a fifth aspect of the present invention, the apparatus further comprises heating means for heating the conductive member.

  According to the said structure, since a heating means heats a conductive member, it can prevent that a water droplet accumulates between conductor members, and can prevent erroneous detection of water immersion by a water droplet.

  According to the invention described in claim 6, the inundation judgment circuit judges that the inundation occurs when the voltage or current of the signal satisfies the judgment condition.

  According to the seventh aspect of the present invention, the inundation determination circuit further needs to satisfy the determination condition a predetermined number of times within a predetermined period.

  According to the above configuration, when the threshold condition is satisfied a predetermined number of times within a predetermined period, it is determined that the water has been submerged, so that erroneous detection can be prevented.

Example 1
FIG. 1 shows a leakage preventing apparatus according to the present invention.

  The leakage prevention apparatus 1 is divided into a high voltage circuit unit 11 that receives power from a high voltage power source and a low voltage circuit unit 13 that receives power from a low voltage power source 12 having a voltage lower than that of the high voltage power source. The high-voltage circuit unit 11 mainly includes a power module 21, a drive board 22, a capacitor 23, an input connector 24 connected to a high-voltage power supply (not shown), and an output connector 25 that outputs power converted by the power module 21. It consists of. The power module 21 includes a plurality of switching elements 26 and a resin case 27 that houses the plurality of switching elements 26. The high-voltage circuit unit 11 includes an energization unit 33 through which a high-voltage current flows, and the energization unit 33 of the power module 21 includes a lowermost-end energization unit 34 that is positioned at the lowest position among the energization units 33. The switching element 26 is positioned on the pedestal portion 38 and is attached to a conductive pattern (not shown) attached on the pedestal portion 38. The lowest end energizing portion 34 hits the boundary surface between the pedestal portion 38 and the switching element 26.

  The high-voltage DC power input through the input connector 24 is smoothed by the capacitor 23. The smoothed DC power is input to the power module 21 configured by a switching element that is driven by a gate signal from the drive substrate 22 and is converted into AC power. The AC power that has been subjected to power conversion is output to a motor (not shown) via an output connector to drive the motor.

  The control board 31 constituting the low-voltage circuit unit 13 is disposed above the lowermost end energization unit 34 and transmits a control command to the drive board 22. The drive board 22 transmits a gate signal to the switching element 26 according to the control command, and drives the switching element 26.

  Next, the flood detection unit 32 will be described. One end of the inundation detection unit 32 is connected to an inundation determination circuit 36 incorporated in the control board 31. Further, the other end of the inundation detection unit 32 extends toward the bottom surface of the inverter case 35, and the front end thereof serves as a detection unit 37 in which the conductive member is exposed. The detection unit 37 is located below the lowermost end energization unit 34. The inundation detection unit 32 provides a potential difference between two opposing conductive members, that is, between the inundation detection unit 32 and the case 35. In the present embodiment, as shown in FIG. 2, the inundation detection unit 32 includes the low-voltage power supply 12, so that the inundation detection unit 32 has a higher potential than the case 35, and A potential difference is applied. The inundation detection unit 32 detects that the water has been submerged to a predetermined position below the lowermost end energization unit 34 and transmits a signal to the inundation determination circuit 36. In a normal time when no flooding occurs, the flood detection unit 32 transmits a signal whose voltage is H level to the flood determination circuit 36 based on the low-voltage power supply 12. On the other hand, as shown in FIG. 3, in the event of an abnormality in which the flooding occurs and the case 35 and the detection unit 37 are short-circuited, the flooding detection unit 32 is grounded to the case 35 side. The signal is transmitted to the inundation determination circuit 36.

  Next, the flood determination circuit 36 will be described. The inundation determination circuit 36 determines the presence or absence of inundation based on a signal transmitted from the inundation detection unit 32. The inundation determination circuit 36 determines that the signal is normal when a signal having an H level voltage is received, and is inundated when a signal having an L level voltage is received. In the present embodiment, the condition for determining the inundation is that the voltage of the input signal to the inundation determination circuit 36 is equal to or lower than a predetermined voltage. In addition, you may use an electric current instead of a voltage for the criteria for immersion. Thus, the inundation determination circuit 36 determines that the inundation occurs when the voltage or current of the signal satisfies a predetermined determination condition. The inundation determination circuit 36 may determine that it is inundated when the determination condition is satisfied a predetermined number of times within a predetermined period. By making the determination a plurality of times, the risk of erroneous detection can be reduced.

  If the inundation determination circuit 36 determines that the inundation has occurred, a fail signal is transmitted to the ECU (not shown). The ECU that has received the fail signal shifts to a procedure necessary for preventing leakage.

As described above, since the leakage prevention device 1 detects flooding before the high-voltage circuit unit 11 and the low-voltage circuit unit 13 are flooded, it is possible to take an early leakage prevention measure.
(Example 2)
FIG. 6 shows a leakage preventing apparatus according to Embodiment 2 of the present invention shown in FIG. In the inverter case 35 of the second embodiment, the left bottom surface is higher than the right bottom surface. The capacitor 23 is disposed on the right bottom surface, and the power module 21 is disposed on the left bottom surface. A drive board 22 is arranged above the power module, and a control board 31 is arranged on the drive board 22. As a result of the height of the bottom surface on the left side, the drive board 22 is located above the upper surface of the capacitor 23, and the output connector 25 is located above the input connector 24. The bottom surface on which the power module 21 is disposed is higher than the bottom surface on which the capacitor 23 is disposed. Therefore, in the second embodiment, the lower energization portion 33 of the energization portions 33 of the input connector is the lowermost end energization portion 34.

In the second embodiment, a pointed portion 40 with a thin tip is provided on the case side toward the inundation detection unit 32. As described above, at least one of the two conductive members facing each other has the pointed portion 40 whose tip is narrowed toward the other, so that water droplets can be prevented from adhering between the two conductive members facing each other.
(Modification)
The electric leakage prevention apparatus 1 may have a blowing unit that blows air to a portion where the distance is minimum between the two conductive members. An example of the blowing means is a blowing fan.

  Furthermore, you may provide the heating means which heats an electricity supply member. Excess water can be removed by heating the water immersion detection unit 32 and the conductive member facing the water detection unit 32. In an inverter or the like, an energized element operates to generate high heat. Therefore, such an element may be used as a heating unit, and an energizing member may be disposed near the heating unit.

  By the blowing means and the heating means, it is possible to prevent water droplets or the like due to dew condensation from adhering between the infiltration detection unit 32 and the case and erroneously detecting as inundation.

  In order to prevent the detection part 37 of the inundation detection part 32 exposed to the conductive member from being oxidized and corroded to reduce the detection sensitivity, the surface is covered with a thin film of metal that is less susceptible to oxidation than the metal of the conductive member. It may be coated.

  The shape of the inundation detection unit 32 may be a rod-shaped conductor or a conductor that easily vibrates, such as a lead wire. In the case where the inundation detection unit 32 is a rod-shaped conductor, there is an advantage that there is little possibility that the inundation detection unit 32 is displaced due to vibration or the like and grounded with the surrounding conductors for erroneous detection. On the other hand, when the inundation detection unit 32 is a vibrating body such as a lead wire, an effect such as shaking off the water droplet can be expected even when the water droplet adheres. In this case, since the terminal portion of the lead wire may be grounded to surrounding equipment or the like, it is desirable to cover the terminal portion of the lead wire with a hollow insulator or the like that opens downward.

BRIEF DESCRIPTION OF THE DRAWINGS It is a longitudinal cross-sectional view of the electrical-leakage prevention apparatus of the electric equipment which concerns on Example 1 of this invention. It is a normal inundation detection part which concerns on Example 1 of this invention. It is a flooding detection part at the time of flooding which concerns on Example 1 of this invention. It is a longitudinal cross-sectional view of the electrical-leakage prevention apparatus of the electric equipment which concerns on Example 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Leakage prevention apparatus 11 High voltage circuit part 12 Inundation judgment circuit 13 Low voltage circuit part 32 Inundation detection part 33 Current supply part 34 Bottom end current supply part 36 Inundation determination circuit 40 Pointed part

Claims (7)

A high-voltage circuit unit that receives power supply from a high-voltage power source, and a low-voltage circuit unit that receives power supply from a low-voltage power source having a voltage lower than the high-voltage power source to control the high-voltage circuit unit;
An inundation detection unit for detecting that the submerged position is lower than a lowermost end energization unit among the energization units through which a high-voltage current flows in the high-voltage circuit unit;
An inundation determination circuit connected to the low-voltage circuit unit disposed above the lowest-end energization unit, and determining inundation based on a signal from the inundation detection unit;
An electrical leakage prevention apparatus for electrical equipment, comprising: The inundation detection unit is
2. The leakage preventing device for an electric device according to claim 1, wherein a potential difference is applied between the two conductive members facing each other.   The leakage preventing device for an electric device according to claim 2, wherein at least one of the two opposing conductor members is a pointed end with a tip becoming narrower toward the other.   4. The electrical leakage prevention device for an electrical device according to claim 2, further comprising a blowing unit that blows air to a portion where the distance is minimum between the two conductive members.   The electrical leakage prevention device for an electrical device according to any one of claims 2 to 4, further comprising heating means for heating the conductive member.   6. The leakage preventing device for an electrical device according to claim 1, wherein the flood determination circuit determines that the signal is flooded when a voltage or current of the signal satisfies a determination condition. 7.   The leakage prevention device for an electrical device according to claim 6, wherein the inundation determination circuit further needs to satisfy the determination condition a predetermined number of times within a predetermined period.

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