JP5104520B2 - Electric vehicle charging device - Google Patents

Description

  The present invention relates to a charging device that charges a secondary battery mounted on an electric vehicle.

  An electric vehicle such as an electric vehicle that drives the vehicle with a motor is equipped with a chargeable / dischargeable secondary battery as a drive source for driving the motor. Since the secondary battery is discharged as the vehicle travels, it is necessary to charge the battery when the remaining capacity decreases to a predetermined capacity. For this reason, the electric vehicle is equipped with an in-vehicle charger that converts AC to DC and adjusts the voltage to the charging voltage of the secondary battery, and can be connected to an external AC power source for charging. ing.

  In general, an AC power source is often grounded at a neutral point in order to suppress abnormal voltage in the event of a power distribution system failure. When a vehicle charger mounted on an electric vehicle is connected to such an AC power source and charging is performed, if an AC wiring leaks to the vehicle body, an AC potential from an external AC power source may be generated in the electric vehicle. is there. In order to eliminate this AC potential, the vehicle is connected to the ground line of the external power supply, and the leakage current leaked from the AC wiring to the vehicle is released from the ground line of the AC power supply to the ground. An earth leakage circuit breaker that cuts off is provided. Also, when a grounding wire is provided for the electromagnetic relay that cuts off the AC power line and the grounding wire on the external power supply side becomes abnormal, such as disconnection, a leakage current is released from the vehicle to the ground via the grounding wire of the electromagnetic relay. There has been proposed a method of interrupting an AC electric wire with an electromagnetic relay (see, for example, Patent Document 1).

JP-A-7-123517

  In order to prevent the occurrence of an AC potential due to leakage from the AC electric wire to the vehicle, a ground wire is directly connected to the vehicle body. In this case, the leakage current leaked from the AC electric wire to the vehicle is released to the ground via the ground wire directly connected to the vehicle body. However, if there is an abnormality such as a break in the ground wire directly connected to the vehicle body, the leakage current cannot be released to the ground.

  The case where the electric vehicle 100 is charged by such a conventional technique will be described with reference to FIG. As shown in FIG. 3, the external power source is supplied to the pole transformer 21 of the utility pole using, for example, an AC 600V high-voltage cable, transformed to AC 200 V by the pole transformer 21, and supplied as power for the building 31. A neutral point 22 of the coil of the pole transformer 21 is grounded by a ground wire 23 to a first ground point 24 near the power pole. The pole transformer 21 includes a neutral end 26 connected to the neutral point 22 and two voltage ends 25a and 25b. The neutral end 26 is connected to the service port 32 of the building 31 by a cable 28, and the voltage terminals 25a and 25b are connected to the service port 32 by cables 27 and 29, respectively. In the case of such a power distribution system, when electric power is taken out from between the cables 27 and 29 connected to the voltage terminals 25a and 25b, AC 200V electric power can be taken out, and one cable 27 and the neutral point can be taken out. When power is taken out from the connected cable 28, AC 100V power can be taken out.

  As shown in FIG. 3, the cable 27 and the cable 28 are connected to the power distribution system of the building 31 via the earth leakage breaker 33 provided in the building 31, and the power distribution system of the building 31 is electrically connected to the voltage terminal 25a. And a cable 42 electrically connected to the neutral end 26. The cable 41 and the cable 42 supply AC 100V power to the power distribution system of the building 31. Further, the building 31 is provided with a grounding wire 43 connected to the second grounding point 44 so that when there is a leak in the building 31 from the cables 41 and 42, the leakage current can be released to the ground. It is configured.

  The cable 41 and the cable 42 are connected to the voltage-side vehicle charging wiring 16 and the ground-side vehicle charging wiring 17 via the leakage breaker 34, and the wirings 16 and 17 are each a charger mounted on the electric vehicle 100. 11 is connected to the voltage terminal 12 and the ground terminal 13. The voltage side vehicle charging wiring 16 and the ground side vehicle charging wiring 17 constitute a vehicle charging wiring 15. The earth leakage breaker 34 is a circuit breaker that cuts off each of the wirings 16 and 17 from an ammeter that detects a leakage current by measuring a current of a coil passing through the voltage side vehicle charging wiring 16 and the ground side vehicle charging wiring 17. And a test line 36 in which the cable 41 and the ground-side vehicle charging wiring 17 are connected via a limiting resistor 38 and a test switch 37. The charger 11 includes therein a power converter that converts AC power into DC power, and a voltage converter that adjusts the voltage to the charging voltage of the secondary battery 14 mounted on the electric vehicle 100. The secondary battery 14 is charged.

  As shown in FIG. 3, one end of electric vehicle 100 is directly connected to vehicle body 10, and the other end is connected to ground line 43 of building 31, and electrically connects vehicle body 10 and second ground point 44. A vehicle body ground line 18 is provided.

  An operation in the case where the secondary battery 14 mounted on the electric vehicle 100 is charged by the charging system configured as described above will be described. Before starting charging, the test switch 37 of the earth leakage breaker 34 on the connection side of the charger 11 is turned on, and the current from the cable 41 through the limiting resistor 38 to the ground side vehicle charging wiring 17 as shown by the arrow in FIG. Shed. Then, the current detector of the leakage breaker 34 detects the current based on this current, and confirms whether the breaker operates. During the operation test of the earth leakage breaker 34 by the test switch 37, no current flows through the vehicle body grounding line 18. For this reason, in the operation test of the earth leakage breaker 34, it cannot be confirmed whether the vehicle body grounding wire 18 is electrically connected to the second grounding point 44 without any abnormality.

  Therefore, the potential between the ground wire 43 or the vehicle body ground wire 18 of the building 31 electrically connected to the second ground point 44 and the cable 42 electrically connected to the neutral point of the pole transformer 21. Measure. Since the neutral point 22 is electrically connected to the first ground point 24 by the ground line 23, if there is no potential difference between the first ground point and the second ground point, the measured potential should be zero. It can be confirmed that the vehicle body grounding wire 18 is grounded without any abnormality. When the vehicle body grounding wire 18 is electrically connected to the second grounding wire without any abnormality, when a leakage occurs from the voltage-side vehicle charging wiring 16 to the vehicle body 10, the leakage current is indicated by the arrow in FIG. Then, the vehicle body 10 is released to the ground through the vehicle body grounding line 18.

  However, since the first ground point 24 and the second ground point 44 are different points, a potential difference ΔV may occur between the first ground point 24 and the second ground point 44. In such a case, even when the measured potential difference between the vehicle body grounding wire 18 and the cable 42 becomes zero, the vehicle body grounding wire 18 may be abnormal. Conversely, even when the measured potential difference is not zero, the vehicle body There may be no abnormality in the grounding wire 18. For this reason, there is a problem that it is not possible to confirm the presence or absence of abnormality of the vehicle body grounding wire 18 by measuring the potential difference between the vehicle body grounding wire 18 and the cable 42. If there is an abnormality in the vehicle body grounding wire 18 and it is not electrically connected to the second grounding point 44, if a leak occurs in the vehicle body 10 from the voltage-side vehicle charging wiring 16, an AC potential is applied to the vehicle body 10. There was a problem that would occur.

  An object of the present invention is to easily determine whether there is an abnormality in a grounding wire connected to a grounding point different from the grounding point of an external power source from the vehicle body.

  The charging device for an electric vehicle according to the present invention is connected to an external power source having a neutral point grounded to a first grounding point via an earth leakage breaker, and charges the secondary battery mounted on the electric vehicle. An electric vehicle, a charger mounted on the electric vehicle, a voltage terminal and a neutral terminal of an external power source, a vehicle charging wiring electrically connecting the voltage terminal and the ground terminal of the charger, and the electric vehicle Mounted on the ground, one end of which is electrically connected to a second grounding point different from the first grounding point of the external power source, one end of which is connected to the body of the electric vehicle, and one end of which is a limiting resistor. A short-circuit wire connected to the voltage-side vehicle charging wiring between the earth leakage breaker and the charger, and a relay for switching the ground wire between the vehicle body connection wire side and the short-circuit wire side, A control unit that performs switching, and the control unit short-circuits the relay before starting charging. The switching, through the short-circuit line from the earth leakage breaker current flows to the ground line, it has a ground confirmation means for confirming the ground operations and ground line fault interrupter, characterized by.

  In the charging device for an electric vehicle according to the present invention, the control unit includes a charging start unit that starts charging after switching the relay to the vehicle body connection line side after connecting the vehicle body connection line and the ground line after the ground confirmation unit. This is also preferable.

  The present invention has an effect that it is possible to easily determine whether there is an abnormality in a grounding wire connected to a grounding point different from the grounding point of the external power source from the vehicle body.

  Preferred embodiments of the present invention will be described below with reference to the drawings. Parts similar to those of the prior art described with reference to FIG. 3 are denoted by the same reference numerals, and detailed description thereof is omitted. As shown in FIG. 1, the charging device 70 of the electric vehicle 100 is mounted on the electric vehicle 100 by being connected to an external power source having a neutral point 22 grounded to the first grounding point 24 via a leakage breaker 34. Charges the secondary battery 14, and includes a charger 11 mounted on the electric vehicle 100, a vehicle charging wiring 15 that connects the external power source and the charger 11, a relay 50 mounted on the vehicle, and a relay 50 And a ground line 19 that electrically connects the second ground point 44 different from the first ground point 24 of the external power source, a vehicle body connection line 56 that connects the relay 50 and the vehicle body 10 of the electric vehicle 100, and a limiting resistor 55. Including a short-circuit line 54 that connects the relay 50 and the voltage-side vehicle charging wiring 16, an ammeter 57 that detects the current in the vehicle charging wiring 15, and a control unit 60 that switches the relay 50. Yes.

  As shown in FIG. 1, for example, an external power source is supplied to a pole transformer 21 of a utility pole by a high voltage AC 600 V cable, transformed to 200 V AC by the pole transformer 21, and a building is constructed by three cables 27, 28, and 29. This is AC 100V power supplied from the cables 41 and 42 of the power distribution system of the building 31 connected to the two cables 27 and 28 of these.

  Here, the neutral point 22 of the coil of the pole transformer 21 is grounded to the first ground point 24 near the power pole by the ground wire 23. The pole transformer 21 includes a neutral end 26 connected to the neutral point 22 and two voltage ends 25a and 25b. The neutral end 26 is connected to a cable 28, and the voltage ends 25a and 25b are connected to cables 27 and 29, respectively. Further, the building 31 is provided with a grounding wire 43 connected to the second grounding point 44 so that when there is a leak in the building 31 from the cables 41 and 42, the leakage current can be released to the ground. It is configured.

  AC 100V power supplied from the cables 41 and 42 is connected to the voltage-side vehicle charging wiring 16 and the ground-side vehicle charging wiring 17 via the leakage breaker 34, and the wirings 16 and 17 are respectively connected to the electric vehicle. The battery terminal 11 is connected to the voltage terminal 12 and the ground terminal 13 of the charger 11. The voltage side vehicle charging wiring 16 and the ground side vehicle charging wiring 17 constitute a vehicle charging wiring 15. The charger 11 includes an internal power converter that exchanges AC power with DC power, and a voltage converter that adjusts the voltage to the charging voltage of the secondary battery 14 mounted on the electric vehicle 100, and the supplied AC power. To charge the secondary battery 14.

  A relay 50 is attached to the electric vehicle 100. The relay 50 is provided with three contacts 51, 52, 53 and one end connected to the contact 51, and a movable conductive plate 58 capable of switching the other end connection between the contact 52 and the contact 53. A ground wire 19 connects the contact point 51 of the relay 50 and the ground wire 43 of the building 31. Since the ground wire 43 of the building 31 is connected to the second ground point 44, the ground wire 19 electrically connects the contact point 51 and the second ground point 44. The contact 52 of the relay 50 and the voltage side vehicle charging wiring 16 are connected by a short-circuit line 54 provided with a limiting resistor 55. The short-circuit line 54 is connected to the voltage-side vehicle charging wiring 16 between the leakage breaker 34 and the charger 11, and is configured such that a short-circuit current flows from the distribution system of the building 31 through the leakage breaker 34. Yes. The contact 53 of the relay 50 and the vehicle body 10 of the electric vehicle 100 are connected by a vehicle body connection line 56. The ammeter 57 provided in the vehicle charging wiring 15 may detect a short circuit current by measuring a current of a coil penetrating the voltage side vehicle charging wiring 16 and the ground side vehicle charging wiring 17. However, it is also possible to measure individual currents of the wirings 16 and 17.

  The control unit 60 may be a computer including a CPU and a memory that stores programs, data, and the like, or may be configured by an electric circuit. The relay 50, the ammeter 57, and the charger 11 are connected to the control unit 60, and the relay 50 is configured to be able to perform a contact switching operation and an on / off operation of the charger 11 according to a command from the control unit 60. . Further, the control unit 60 is configured to be able to acquire the current value detected by the ammeter 57.

  The operation of the charging device 70 of the electric vehicle 100 configured as described above will be described with reference to FIG. As shown in step S <b> 101 of FIG. 2, the control unit 60 outputs a command to switch the relay 50 so that the other end of the movable conductive plate 58 attached to the contact 51 of the relay 50 is in contact with the contact 52. In response to this command, the relay 50 operates, and the movable conductive plate 58 is switched to connect the contact 51 and the contact 52. When there is no abnormality in the ground wire 19, when the contact 51 and the contact 52 are connected, the short-circuit current is short-circuited from the voltage-side vehicle charging wiring 16 through the limiting resistor 55 as shown by the arrow in FIG. 1. It flows to the second ground point 44 from the contact 52 through the contact 51 and the ground line 19. And the ammeter provided in the earth leakage circuit breaker 34 detects a short circuit current, the circuit breaker of the earth leakage circuit breaker 34 is opened, and the wiring 15 for vehicle charging is interrupted.

  As shown in step S <b> 102 of FIG. 2, the control unit 60 detects a short-circuit current that flows from the voltage-side vehicle charging wire 16 to the short-circuit wire 54 with an ammeter 57 provided in the vehicle charging wire 15. The short-circuit current is detected when the relay 50 is switched to the short-circuit line 54 side, and is not detected when the vehicle charging wiring 15 is interrupted by the leakage breaker 34. From this, as shown in step S103 of FIG. 2, the control unit 60 operates normally when the short circuit current is detected after switching the relay 50 and the short circuit current is not detected after that. Judge that it was done. At the same time, it is determined that the ground line 19 is connected to the second ground point 44 without any abnormality.

  As shown in step S104 of FIG. 2, the control unit 60 determines that the earth leakage breaker 34 operates normally and the ground wire 19 is electrically connected to the second ground point 44 without any abnormality. A command to switch the relay 50 is output so that the other end of the movable conductive plate 58 attached to the contact 51 of the relay 50 is in contact with the contact 53. The relay 50 is operated by this command, and the movable conductive plate 58 is switched to connect the contact 51 and the contact 53. Then, the ground wire 19 is connected to the vehicle body 10 through the relay 50, and even if a leak occurs in the vehicle body 10 from the voltage-side vehicle charging wiring 16, the leakage current flowing in the vehicle body 10 is changed from the ground wire 19 without abnormality. 2 can flow to the grounding point 44, and an AC potential can be prevented from being generated in the vehicle body 10.

  As shown in step S105 in FIG. 2, the control unit 60 outputs a command to start charging. By this command, the charger 11 is turned on, and the charger 11 is supplied with AC power supplied to the voltage terminal 12 and the ground terminal 13 of the charger 11 by the voltage-side vehicle charging wiring 16 and the ground-side vehicle charging wiring 17. Is converted to DC power, and charging of the secondary battery 14 is started.

  On the other hand, when the ground line 19 is abnormal, the relay 50 operates and the movable conductive plate 58 is switched to connect the contact 51 and the contact 52, and even if the contact 51 and the contact 52 are connected, a short circuit occurs. The current does not flow from the voltage-side vehicle charging wiring 16 through the limiting resistor 55 to the short-circuit line 54 and the contact 52, and the leakage breaker 34 does not operate. Also, the ammeter 57 does not detect a short circuit current. Therefore, as shown in step S103 of FIG. 2, after the switching of the relay 50, the control unit 60 has an abnormality in the ground line 19 when the short-circuit current is not detected, and the contact 51 is at the second ground point 44. Judge that it is not connected.

  The control unit 60 outputs a command for switching the relay so that the other end of the movable conductive plate 58 attached to the contact 51 of the relay 50 is in contact with the contact 53 as shown in Step S <b> 106 of FIG. 2. The relay 50 is operated by this command, and the connection between the contact 51 and the contact 52 is released. Then, as shown in step S107 of FIG. 2, the control unit 60 stops the charging operation.

  As described above, in the present embodiment, the ground line 19 connected to the voltage side vehicle charging wiring 16 via the relay 50 from the vehicle body 10 to the second ground point 44 different from the first ground point 24 of the external power source. Can be connected to the ground line 19 without passing a short-circuit current through the vehicle body 10 to check whether the ground wire 19 is abnormal. Therefore, the second connection different from the first ground point 24 of the external power source from the vehicle body 10 can be performed. There is an effect that it is possible to easily determine whether or not the ground wire 19 connected to the point 44 is abnormal. In addition, since the operation of the earth leakage breaker 34 can be confirmed together with the confirmation of the abnormality of the grounding wire 19, it is possible to effectively suppress the generation of an AC potential in the vehicle body 10 due to the leakage at the time of charging.

  In the embodiment described above, the control unit 60 has been described as detecting the short-circuit current by the ammeter 57 provided in the vehicle charging wiring 15, but the ammeter provided in the leakage breaker 34 is used as the control unit 60. It is good also as detecting short circuit current so that it may connect.

It is a systematic diagram which shows the structure of the charging device of the electric vehicle in embodiment of this invention. It is a flowchart which shows operation | movement of the charging device of the electric vehicle in embodiment of this invention. It is a systematic diagram which shows the system | strain structure at the time of charging the secondary battery of an electric vehicle by a prior art.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Car body, 11 Charger, 12 Voltage end, 13 Ground end, 14 Secondary battery, 15 Vehicle charge wiring, 16 Voltage side vehicle charge wiring, 17 Ground side vehicle charge wiring, 18 Vehicle body ground wire, 19, 23 , 43 Ground wire, 21 Pillar transformer, 22 Neutral point, 24 First ground point, 25a, 25b Voltage end, 26 Neutral end, 27, 28, 29, 41, 42 Cable, 31 Building, 32 Service entrance, 33, 34 Earth leakage breaker, 35 Main body, 36 Test line, 37 Test switch, 38, 55 Limiting resistor, 44 Second ground point, 50 Relay, 51, 52, 53 Contact, 54 Short circuit wire, 56 Body connection wire, 57 Ammeter, 58 movable conductive plate, 60 controller, 70 charging device, 100 electric vehicle.

Claims (2)

A charging device for an electric vehicle that is connected to an external power source having a neutral point grounded to a first ground point through an earth leakage breaker and charges a secondary battery mounted on the electric vehicle,
A charger mounted on an electric vehicle;
Vehicle charging wiring that electrically connects the voltage end and neutral end of the external power source, and the voltage end and ground end of the charger, respectively.
Mounted on an electric vehicle, one end is electrically connected to a second grounding point different from the first grounding point of the external power supply, one end is connected to the body of the electric vehicle, and one end is limited A short-circuit wire connected to the voltage-side vehicle charging wiring between the earth leakage breaker and the charger via the resistor, and a relay that switches the ground wire between the vehicle body connection line side and the short-circuit line side;
A control unit for switching the relay,
The control unit
Before starting charging, switch the relay to the short-circuit line side, let the current flow from the earth leakage breaker to the ground line through the short-circuit line, and have grounding confirmation means to check the operation of the earth leakage breaker and the grounding wire ground,
An electric vehicle charging device. The charging device for an electric vehicle according to claim 1,
The control unit
After the ground confirmation means, having a charging start means for starting charging after switching the relay to the vehicle body connection line side and connecting the vehicle body connection line and the ground line,
An electric vehicle charging device.

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