JP6119479B2 - Electric vehicle charger - Google Patents

Description

  The present invention relates to a charging device for an electric vehicle that includes a plurality of power supply lines for charging by connecting to an electric vehicle, and selecting and using a power supply destination.

  2. Description of the Related Art Conventionally, a number of charging devices for electric vehicles for connecting and charging a battery provided in an electric vehicle have been proposed.

  Since an electric vehicle requires a large output, a battery to be used has a high voltage of about 500 V at the maximum. Therefore, a charging device for an electric vehicle also supports a high voltage. In addition, in order to shorten the charging time, many have a function of performing rapid charging that allows a large current to flow. As described above, since a charging device for an electric vehicle is generally required to cope with a high voltage and a large current, there is no danger of an electric shock or damage to the device for a person handling the charging device. Many measures have been taken.

  On the other hand, in recent years, in order to improve the convenience of charging an electric vehicle, it is provided with a plurality of power supply lines branched from a single electric vehicle charging device, and a disconnection switch for selecting the power supply line. Thus, there has also been proposed a charging device for an electric vehicle in which the power supply destination can be changed (Patent Document 1). By doing so, it is possible to change the electric vehicles to be charged one after another without the need to move the electric vehicle, and to perform charging efficiently.

Utility Model Registration No. 3151047

  However, as described above, since the charging device for electric vehicles handles high voltage and large current, the connection / disconnection switch used for changing the power supply destination is a circuit in which contacts are welded by long-term use. May not be able to be disconnected. Therefore, when charging an electric vehicle, electric power is output from the power supply line that should be in a disconnected state, and if the end of the power supply line is in contact with something, leakage can occur. There is sex.

  Since it is necessary to maintain a high level of safety for an electric vehicle charging device, it is common to have a function of detecting electric leakage and stopping output, but as described above, in order to take multiple measures For this reason, it is preferable not to perform charging by detecting that the connection / disconnection switch has been welded even before leakage occurs.

  An object of the present invention is to effectively solve such a problem. Specifically, on the premise that a power supply destination can be selected and switched from a plurality of power supply lines, the connection / disconnection switch is welded. The purpose of this is to avoid in advance danger due to electric shock or damage to equipment due to leakage from the standby power supply line.

  In order to achieve this object, the present invention takes the following measures.

  That is, the electric vehicle charging device of the present invention is configured to be capable of outputting a DC power of a predetermined voltage based on energy obtained from an AC power source connected upstream and stopping the output of the DC power. DC power output unit, a plurality of charging connectors for connecting to an electric vehicle, a plurality of connecting / disconnecting switches connected to a branch line branching from the DC power output unit, and connecting / disconnecting switches from these connecting / disconnecting switches to the charging connector A power supply line that supplies power to the power supply, and a control unit that operates the DC power output unit and selectively connects the connection / disconnection switch to supply DC power to a desired charging connector. The control means detects a potential in the power supply line downstream from each connection / disconnection switch, and outputs a potential detection value as a potential detection value; A potential abnormality determination unit that determines potential abnormality based on the potential detection value by the position detection unit, and when the potential abnormality determination unit determines that there is a potential abnormality, output of DC power from the DC power output unit It is characterized by being configured to stop.

  In the present invention, an energy source side for charging an electric vehicle is referred to as an upstream side, a charging connector to which electric power obtained from the energy source is supplied, and an electric vehicle side connected thereto is referred to as a downstream side. Further, even a standby charging connector that is not connected to the electric vehicle is considered as a downstream side, similarly to the charging connector that is connected to the electric vehicle.

  With this configuration, the supply destination of the DC power obtained from the DC power output unit can be switched by the connection / disconnection switch and supplied to the charging connector via a desired power supply line, and the disconnection that should be in the disconnected state can be performed. By determining whether a potential abnormality has occurred based on the potential detection value of the power supply line downstream of the contact switch, it is possible to detect the welding of the connection switch. And, since it is configured to stop the output of DC power when it is determined that a potential abnormality has occurred, there is a risk of electric shock or equipment damage due to leakage from the standby power supply line in advance. It is possible to avoid it.

  Furthermore, in order to make it possible to more easily determine the potential abnormality and to make a determination in a short time while making the control means inexpensive and simple, the potential abnormality determination unit is more than the DC power output unit. When outputting DC power, it is preferable that the potential abnormality is determined when the potential of the power supply line on the downstream side of the disconnected switch in the disconnected state is equal to or higher than a predetermined threshold.

  Also, while improving safety when outputting high-voltage DC power, check in detail whether the connection / disconnection switch is operating properly, and do not charge if there is a malfunction due to welding In order to make it possible, the branch line from the DC power output unit to the connection / disconnection switch, and the power supply line from each connection / disconnection switch to the charging connector are respectively connected to the high voltage line and the low voltage line. Each connecting / disconnecting switch is composed of a high voltage side switch element provided on the high voltage line and a low voltage side switch element provided on the low voltage line, and DC power is output from the DC power output unit. In the case, each potential in the high voltage line and the low voltage line constituting the branch line is different from a reference potential, and the potential abnormality determination unit is in a disconnected state. If the potential difference between the high voltage line and a low voltage line constituting the power supply line downstream of the contact switch is equal to or larger than the threshold value, it is preferable to configured to determine that the potential abnormality.

  In addition, while maintaining a stable state while generating a potential difference between the ground portion set as the reference potential and the high voltage line and the low voltage line, it is possible to more easily detect when the connection switch is welded. In order to enable this, the high voltage line and the low voltage line constituting the power supply line downstream from the connection / disconnection switch are configured to be electrically connected to the grounding part via the grounding resistor, respectively. It is preferable to do.

  Further, in order to achieve both determination of potential abnormality due to welding of the connection / disconnection switch and determination of leakage current at the same time, an output line from the DC power output unit to the connection / disconnection switch is provided. The high-voltage line and the low-voltage line that are configured are electrically connected to the grounding part via a ground fault resistance, respectively, and the resistance value of these ground fault resistances is set smaller than the resistance value of the ground resistance, The control means includes a ground fault current detection unit that detects a current flowing through the ground fault resistance and a ground fault abnormality determination unit that determines a ground fault abnormality based on a current detection value by the ground fault current detection unit. Is preferred.

  According to the present invention described above, by switching the connection state of the connection / disconnection switch, it is possible to change the power supply destination from a plurality of power supply lines, while detecting an abnormality due to welding of the connection / disconnection switch, It is possible to avoid in advance danger due to electric shock or damage to equipment due to electric leakage from the power supply line.

The schematic diagram which shows the structure of the charging device for electric vehicles in 1st Embodiment of this invention. The flowchart which shows the flow of the self-diagnosis in the charging device for the electric vehicles. 6 is a timing chart when no potential abnormality is detected in the self-diagnosis. The timing chart at the time of detecting potential abnormality (welding) in the self-diagnosis. The schematic diagram which shows the structure of the charging device for electric vehicles in 2nd Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment>
The electric vehicle charging apparatus according to the first embodiment of the present invention has a circuit configuration as shown in FIG. The electric vehicle charging device 1 is connected to a commercial three-phase AC power supply 8 on the upstream side, generates DC power based on the electric energy obtained from the three-phase AC power supply 8, and is connected to the downstream electric vehicle 9. It is possible to supply to. For this purpose, the electric circuit unit 2 and control means 5 for controlling the electric circuit unit 2 are provided.

  First, the electric circuit unit 2 includes a power converter 31 as a DC power output unit connected to the three-phase AC power supply 8 via an insulating transformer (not shown). The power converter 31 includes a plurality of semiconductor switching elements (not shown), and is suitable for charging by PWM (Pulse Width Modulation) control of each semiconductor switching element in accordance with a command from the control means 5. It is possible to generate DC power having a predetermined voltage. In addition, the output of DC power can be stopped by turning off each switching element.

  On the downstream side of the power converter 31, output lines 22a and 22b for outputting DC power are provided. Among these, the output line 22a constitutes a high voltage line connected to the high voltage side (P side) of the power converter 31, and the output line 22b is connected to the low voltage side (N side) of the power converter 31. Constitutes a low voltage line. Further, the output line 22a constituting the high voltage line is branched from the branch point C1 into two branch lines 23a and 24a. Similarly, the output line 22b constituting the low voltage line is separated from the branch point C2 by two. The branch lines 23b and 24b are branched. The branch lines 23a and 24a together constitute a high voltage line, and the branch lines 23b and 24b constitute a low voltage line.

  The potential difference between the high voltage line (P side) and the low voltage line (N side) can be changed according to the electric vehicle to be charged, and the potential difference between the two is different from the reference potential of the ground part G. It is set to occur. For example, when the output from the power converter 31 is 300V, the potential of the high voltage line (P side) is + 150V with respect to the reference potential, and the potential of the low voltage line (P side) is −− with respect to the reference potential. It is set to 150V.

  The branch lines 23 a and 23 b can be connected to and disconnected from the power supply lines 25 a and 25 b connected to the charging connector 34 via the connection and disconnection switch 32. The connection / disconnection switch 32 is configured as an electromagnetic switch having a plurality of contacts, and includes a high voltage side switch element 32a for connecting / disconnecting the branch line 23a and the power supply line 25a constituting the high voltage line, A low-voltage side switch element 32b for connecting / disconnecting the branch line 23b and the power supply line 25b constituting the voltage line is provided. And according to the command signal from the control means 5 mentioned later, the high voltage side switch element 32a and the low voltage side switch element 32b interlock | cooperate, and an upstream and downstream are electrically connected. Or in a cut state.

  Similarly, the branch lines 24 a and 24 b can be connected and disconnected to the power supply lines 26 a and 26 b connected to the charging connector 35 via the connection and disconnection switch 33. The connection / disconnection switch 33 is also configured as an electromagnetic switch having a plurality of contacts, and a high-voltage side switch element 33a for connecting / disconnecting the branch line 24a and the power supply line 26a constituting the high-voltage line, A low voltage side switch element 33b for connecting and disconnecting the branch line 24b and the power supply line 26b constituting the voltage line is provided. Then, in response to a command signal from the control means 5, the high voltage side switch element 33a and the low voltage side switch element 33b perform an opening / closing operation in conjunction with each other so that the upstream side and the downstream side are electrically connected. It is possible to make a cut state.

  The charging connectors 34 and 35 can be engaged with a charging connector 91 provided on the electric vehicle 9 side, and can be electrically connected to supply electric power for charging. Moreover, the charging connectors 34 and 35 are provided with a locking mechanism (not shown) and can be locked so that the charging connector 91 is not disengaged during charging.

  The electric vehicle 9 generally includes a connection / disconnection switch 92 between the charging connector 91 and the battery 93, and the high-voltage side switch element 92a and the low-voltage side switch element 92b constituting the connection / disconnection switch 92 are closed during charging. It is possible to store the electric power obtained through the charging connector 91 in the battery 93 as an electrically connected state by setting the state.

  Here, the charging device 1 for an electric vehicle according to the present embodiment performs an insulation diagnosis in order to check whether or not the connection from the power converter 31 to the charging connector 91 of the electric vehicle 9 is properly performed when charging. A ground fault detection circuit 43 is provided.

  The ground fault detection circuit 43 is provided in the middle of the output lines 22a and 22b connected to the power converter 31, and includes ground fault resistors 43a and 43b respectively connected to the grounding part G serving as a reference potential. In order to detect a ground fault current Ig flowing between the resistors 43a and 43b and the ground portion G, a current measuring means 43c is configured. The resistance values R7 and R8 of the ground fault resistors 43a and 43b are set to about several kilo ohms. When normal charging is performed, almost no current flows, but foreign matter is caught between the charging connectors 34 and 91. When an insulation failure from the outside occurs, a current flows.

  Moreover, the electric vehicle charging device 1 in the present embodiment includes output voltage detection circuits 41 and 42 for detecting output voltages output from the charging connectors 34 and 35. The output voltage detection circuits 41 and 42 also function as a welding detection circuit for detecting the occurrence of welding in the connection / disconnection switches 32 and 33.

  The output voltage detection circuit 41 is provided between the power supply lines 25a and 25b on the downstream side of the connection / disconnection switch 32 and the ground part G. Similarly, the output voltage detection circuit 42 is the power supply line on the downstream side of the connection / disconnection switch 33. 26a, 26b and the ground part G, and both output voltage detection circuits 41, 42 have the same configuration. The output voltage detection circuit 41 (42) connects the power supply lines 25a, 25b (26a, 26b) and the ground portion G via the ground resistors 41a, 41b (42a, 42b), and also supplies the power supply lines. 25a and 25b (26a and 26b) are connected by an inter-line resistor 41c (42c). The resistance values R1, R2 (R3, R4) of the resistors 41a, 41b (42a, 42b) are set to about several mega Ω. The resistance value R5 (R6) of the resistor 41c (42c) is set to about several hundred kilos to several mega Ω. With this configuration, it is possible to maintain a stable state while differentiating each potential of the power supply lines 25a and 25b (26a and 26b) from the reference potential. The resistance values R1, R2 (R3, R4) are the same, and the circuit is symmetrical on the high voltage side and the low voltage side. Further, a potential measuring means 41d (42d) for measuring a potential difference Vpn1 (Vpn2) at both ends of the inter-line resistor 41c (42c) is provided.

  Since the resistance values R1 to R6 of the resistors 41a to 42c are set sufficiently larger than the resistance values R7 and R8 of the ground fault resistors 43a and 43b described above, an insulation failure occurs and a leakage state occurs. In this case, the ground fault current passes through the ground fault detection circuit 43 with priority. Therefore, although the output voltage detection circuits 41 and 42 that also function as a welding detection circuit are provided, the functions of the ground fault detection circuit 43 are not hindered, and both functions of ground fault detection and welding detection are achieved. It is possible to do.

  The potential difference Vpn1 (Vpn2) obtained by the output voltage detection circuits 41 and 42 is also used for feedback control of the output voltage from the connection / disconnection switch 33 (32) power converter 31 during normal charging. Therefore, it can be used for two purposes of output voltage control and welding detection, and a simpler and cheaper configuration can be achieved.

  In order to cause the electric circuit unit 2 configured as described above to perform a desired operation, the electric vehicle power generator 1 includes a control unit 5 that controls the electric circuit unit 2.

  The control means 5 records a program for realizing each function on a computer-readable recording medium, causes the computer system to read the program recorded on the recording medium and execute it. Here, the “computer system” includes hardware such as an OS, peripheral devices, and an interface that communicates with an in-vehicle computer that manages charging on the electric vehicle side.

  The control means 5 includes a ground fault current detection unit 51, a leakage abnormality determination unit 52, a potential detection unit 53, a potential abnormality determination unit 54, an output destination switching unit 55, and a display unit 56.

  Based on the setting of the charging destination given by an input means (not shown), the output destination switching unit 55 can switch back and forth so that one of the connection switches 32 and 33 is closed and the other is opened. It has become. By doing so, it is possible to selectively determine which charging connector 34, 35 the output from the power converter 31 is supplied to. In the figure, the output from the power converter 31 is set so that the upstream branch lines 23a and 23b and the power supply lines 25a and 25b are electrically connected by closing the connection / disconnection switch 32. The case where it supplies to the electric vehicle 9 from the charging connector 34 via the electric power supply lines 25a and 25b is shown. The other connection / disconnection switch 33 is open, and the upstream branch lines 24a, 24b and the power supply lines 26a, 26b are electrically disconnected. That is, in this figure, the power supply lines 26a and 26b and the charging connector 35 connected to the power supply lines 26a and 26b are switched to the next connection / disconnection switches 32 and 33 and wait until the power supply from the power converter 31 is performed. It can be said that it is in the inside. It does not matter whether or not the standby charging connector 35 is connected to the electric vehicle.

  The ground fault current detection unit 51 obtains the detection signal of the ground fault current Ig by the current measuring unit 43c, amplifies it, and outputs it to the leakage fault determination unit 52 as the detected value of the ground fault current Ig. ing. The leakage abnormality determination unit 52 stores therein a predetermined threshold value Ith, and if the detected value of the ground fault current Ig is equal to or greater than the threshold value Ith, the leakage detection abnormality, that is, the insulation failure is determined. This is displayed on the display unit 56 to that effect, and the output from the power converter 31 is stopped, and an abnormal flag is set for making the charging impossible. When the detected value of the ground fault current Ig is equal to or greater than the threshold value Ith, it is determined that the state is normal, and the output from the power converter 31 is not stopped or an abnormal flag is not set.

  Note that the control means 5 is configured so that it is impossible to charge the electric vehicle 9 when the abnormality flag is set. Further, instead of the display unit 56, it is possible to configure as a notification unit that notifies an abnormality by an alarm, a lamp, or the like.

  The potential detector 53 obtains detection signals of the potential differences Vpn1 and Vpn2 at both ends of the inter-line resistors 41c and 42c by the potential measuring means 41d and 42d, amplifies them, and determines potential abnormality as detected values of the potential differences Vpn1 and Vpn2. It is possible to output to the unit 54. The potential abnormality determination unit 54 stores therein a threshold Vth of a predetermined potential difference, and of the potential differences Vpn1 and Vpn2, the standby power supply line connected to the open / close switch 33 in the open state. The detected value of the potential difference Vpn2 on the 26a, 26b side is compared with the threshold value Vth. Of course, instead of the connection / disconnection switch 33, when the connection / disconnection switch 32 side is in the open state, the detected value of the potential difference Vpn1 on the power supply lines 25a, 25b side is compared with the threshold value Vth. If the detected value of the potential difference Vpn2 on the power supply lines 26a and 26b on standby is equal to or greater than the threshold value Vth, it is determined that the welding is abnormal, and that effect is displayed on the display unit 56, and the power converter The output from 31 is stopped, and an abnormality flag is set to make the charging impossible state. When the detected value of the potential difference Vpn2 is less than the threshold value Vth, the normal state is determined, and the output from the power converter 31 is not stopped or the abnormality flag is not set.

  Here, the power supply lines 25a and 25b (26a and 26b) are composed of a high voltage line 25a (26a) and a low voltage line 25b (26b), and each generates a potential difference between the reference potential. Therefore, even when only one of the high voltage side switch element 32a (33a) and the low voltage side switch element 32b (33b) constituting the connection / disconnection switch 32 (33) is welded, it is larger than the threshold value Vth. The potential difference Vpn1 (Vpn2) can be obtained.

  The control means 5 configured as described above performs an operation in a self-diagnosis mode for determining whether or not charging is possible as shown in the flowchart of FIG. 2 when a command for starting charging is given. It is composed. The self-diagnosis mode is performed prior to the normal charging mode, and confirms whether there is an abnormality in the connection state between the internal circuit and the electric vehicle 9. FIGS. 3 and 4 show timing charts of detection signals obtained during the self-diagnosis mode and operation command signals to be output.

  First, the normal operation in the self-diagnosis mode will be described with reference to FIGS.

  When an instruction to start charging is given through an input unit (not shown) (FIG. 3A), the control unit 5 exchanges information with the vehicle (electric vehicle 9) (ST1). By doing so, it is possible to obtain information necessary for charging, such as the voltage, capacity, and storage amount of the battery 93 included in the electric vehicle 9. At this point, the connection / disconnection switch 92 on the electric vehicle 93 side remains in the disconnected state, and does not shift to the connected state until it is determined that the self-diagnosis mode is in a normal state suitable for charging. ing.

  Then, a locking operation command signal is issued to lock the charging connector 34 connected to the power supply lines 25a and 25b for charging (ST2, FIG. 3B), and the charging connector 91 on the electric vehicle 9 side until the charging is stopped. To prevent disconnection of.

  Then, an operation command signal is sent to the power converter 31 and PWM control of the semiconductor switching element inside the power converter 31 is performed (FIG. 3 (d)), and output of the inspection voltage is started. (ST3). The inspection voltage increases linearly from the start of output, and is maintained at the maximum voltage within a range that can be output by the power converter 31 for several seconds (FIG. 3 (e)).

  While outputting this inspection voltage, the leakage abnormality determination unit 52 determines whether or not the detected value of the ground fault current Ig output from the ground fault current detection unit 51 is less than the threshold value Ith ( ST4). When the detected value of the ground fault current Ig is less than the threshold value Ith and it is determined that there is no leakage abnormality state, the process proceeds to the determination by the next potential abnormality determination unit 54 (ST5). The potential abnormality determination unit 54 determines whether or not the potential difference Vpn2 between the power supply lines 26a and 26b that are standby lines is less than the threshold value Vth. When the potential difference Vpn2 does not appear in the standby side lines (power supply lines 26a and 26b) (FIG. 3 (f)) and is less than the threshold value Vth, the potential switch is not in an abnormal state and the connection / disconnection switch 33 is welded. Judge that it is not normal.

  Thereafter, the test voltage output is stopped to end the self-diagnosis mode (ST6). By doing so, the output voltage from the power converter 31 decreases linearly to zero (FIG. 3E), and the semiconductor switching element in the power converter 31 is also turned off (FIG. d)). Further, in order to set the chargeable state, the abnormality flag is not raised, that is, the state is kept off (ST7).

  Thus, when the self-diagnosis mode is finished with the abnormality flag being off, the normal charging mode is shifted as it is, and charging of the battery 93 included in the electric vehicle 9 is started.

  In this case, the connecting / disconnecting switch 92 on the vehicle (electric vehicle) 9 side is shifted to the on (closed) state (FIG. 3C), and the PWM control of the semiconductor switching element of the power converter 31 is started (FIG. 3). 3 (d)), current output for charging is started from the power supply lines 25a and 25b constituting the charging side line (FIG. 3 (g)).

  Next, the operation at the time of abnormality in the self-diagnosis mode will be described based on FIGS. 2 and 4 with reference to FIG.

  Step of determining whether or not the ground fault current Ig is less than the threshold value Ith through steps of information exchange with the vehicle (ST1), locking of the charging connector (ST2), and start of inspection voltage output (ST3) (ST4) When it is determined that the ground fault current Ig is greater than or equal to the threshold value Ith, “leakage fault” is displayed on the display unit 56 (ST8), and the process proceeds to the next step ST10.

  Similarly, in the determination step (ST5) of whether or not the potential difference Vpn2 between the power supply lines 26a and 26b, which is the standby side line, is less than the threshold value Vth, an output is also made to the potential difference Vpn2 of the standby side line. If Vth is abnormal (FIG. 3 (f)), “switch welding abnormality” is displayed on the display unit 56 (ST9), and the process proceeds to the next step ST10.

  In step ST10 that follows both steps ST8 and ST9, the test voltage output is stopped. By doing so, the output voltage from the power converter 31 decreases linearly to zero (FIG. 4E), and the semiconductor switching element in the power converter 31 is also turned off (FIG. d)).

  Further, in order to set the charging disabled state, an abnormality flag is set, that is, set to the on state (ST11, FIG. 4 (h)), and the charging connector 34 is unlocked, and the processing for charging is stopped. To do. Then, the device is inspected and repaired, and charging cannot be performed until the abnormality flag is reset and turned off.

  As described above, the charging device 1 for an electric vehicle according to the present embodiment outputs the DC power having a predetermined voltage based on the energy obtained from the AC power supply 8 connected to the upstream side, and stops the output of the DC power. Connected to the power converter 31 as a direct current power output unit, a plurality of charging connectors 34 and 35 for connection to the electric vehicle 9, and branch lines 23a to 24b branched from the power converter 31. The plurality of connected / disconnected switches 32 and 33, the power supply lines 25a to 26b for supplying power from the connected / disconnected switches 32 and 33 to the charging connectors 34 and 35, and the power converter 31 are operated and disconnected. Control means 5 for supplying direct-current power to the desired charging connectors 34 and 35 by performing control to selectively connect the contact switches 32 and 33, and The control means 5 detects the potential in the power supply lines 25a to 26b on the downstream side of the connection / disconnection switches 32 and 33 and outputs the potential detection value as a potential detection value, and the potential detection value by the potential detection portion 53 is based on the potential detection value. Is further provided with a potential abnormality determination unit 54 for determining potential abnormality, and when the potential abnormality determination unit 54 determines that there is a potential abnormality, the output of DC power from the power converter 31 is stopped. is there.

  With this configuration, the DC power supply destination obtained by the power converter 31 is switched by the connection / disconnection switches 32 and 33 and supplied to the charging connector 34 via the desired power supply lines 25a and 25b. The connection / disconnection switch 33 can be welded by determining whether a potential abnormality has occurred based on the detected potential values of the power supply lines 26a, 26b downstream of the connection / disconnection switch 33 that should be in the disconnected state. It becomes possible to detect. Then, by stopping the output of the DC power, it is possible to avoid in advance dangers such as electric shock and damage to the equipment due to leakage from the standby power supply lines 26a and 26b.

  Further, when the potential abnormality determination unit 54 outputs DC power from the power converter 31, the potential Vpn2 of the power supply lines 26a and 26b on the downstream side of the disconnection switch 33 in the disconnected state is greater than or equal to a predetermined threshold value Vth. In some cases, since it is configured to determine that the potential is abnormal, the determination of potential abnormality can be performed more easily, and the control means 5 can be made inexpensive and simple, and determination can be performed in a short time. As a result, it is possible to avoid an increase in the time until the start of charging.

  Further, the branch lines 23a to 24b extending from the power converter 31 to the connection switches 32 and 33 and the power supply lines 25a to 26b extending from the connection switches 32 and 33 to the charging connectors 34 and 35 are respectively high voltage lines. 23a, 24a, 25a, 26a and low voltage lines 23b, 24, 25b, 26b, and each of the connection switches 32, 33 is a high voltage side switch element provided in the high voltage lines 23a, 24a, 25a, 26a. 32a, 33a and low voltage side switch elements 32b, 33b provided on the low voltage lines 23b, 24, 25b, 26b, and when DC power is output from the power converter 31, branch lines 25a-26b The potentials in the high voltage lines 23a and 24a and the low voltage lines 23b and 24b constituting the In addition, the potential abnormality determination unit 54 determines that the potential difference Vpn2 between the high voltage line 26a and the low voltage line 26b constituting the power supply lines 26a and 26b downstream of the connection / disconnection switch 33 in the disconnected state is the threshold value Vth. In such a case, since it is configured to determine that the potential is abnormal, by providing the switch elements 33a and 33b in each of the high voltage line 26a and the low voltage line 26b constituting the electric circuit for charging, It becomes possible to improve safety when outputting high-voltage DC power, and even when only one of the switch elements 33a and 33b is welded, the high-voltage line 26a and the low-voltage line 26b are connected. Since a potential difference can be generated, it is possible to detect welding by determining that the potential is abnormal when the potential difference is equal to or greater than a threshold value Vth. It is possible to easily perform.

  Further, the high voltage lines 25a and 26a and the low voltage lines 25b and 26b constituting the power supply lines 25a to 26b on the downstream side of the connection switches 32 and 33 are electrically connected to the ground part G via the ground resistors 41a to 42b, respectively. Since the potentials in the high voltage lines 25a and 26a and the low voltage lines 25b and 26b are different from the reference potential, the connection / disconnection switch 32 can be maintained in a stable state. , 33 can be detected more easily when welding occurs.

  Further, the high voltage line 22a and the low voltage line 22b constituting the output lines 22a and 22b from the power converter 31 to the connection / disconnection switches 32 and 33 are respectively connected to the ground portion G via the ground fault resistors 43a and 43b. The resistance values R7, R8 of these ground fault resistors 43a, 43b are set to be smaller than the resistance values R1-R4 of the ground resistors 41a-42b, and the current flowing through the ground fault resistors R7, R8 is set. Since the control means 5 includes a ground fault current detection unit 51 to detect and a ground fault abnormality determination unit 52 that determines a ground fault abnormality based on a current detection value by the ground fault current detection unit 51, By making the resistance values R7 and R8 of the resistances 43a and 43b smaller than the resistance values R1 to R4 of the ground resistances 41a to 42b, the ground resistances 41a to 42b are prioritized in the case of leakage. Since the current can flow to the ground fault resistors 43a and 43b, the current flowing to the ground fault resistors 43a and 43b is parallel to the determination of the potential abnormality caused by the welding of the connection switches 32 and 33. By detecting it, it is possible to achieve both the determination of the leakage abnormality.

Second Embodiment
The charging device for an electric vehicle according to the second embodiment of the present invention has a circuit configuration as shown in FIG. The electric vehicle charging apparatus 101 includes an electric circuit unit 102 and a control unit 105 that controls the electric circuit unit 102, similarly to the electric vehicle charging apparatus 1 (see FIG. 1) in the first embodiment described above. Further, the electric circuit unit 102 is different from the electric circuit unit 2 (see FIG. 1) of the electric vehicle charging device 1 in the first embodiment only in the output voltage detection circuits 141 and 142. Further, the control means 105 differs from the control means 5 (see FIG. 1) of the electric vehicle charging apparatus 1 in the first embodiment only in the potential detection unit 153 and the potential abnormality determination unit 154. Since points other than these have the same structure as the electric vehicle charging device 1 described in the first embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The output voltage detection circuits 141 and 142 have the same configuration, and the output voltage detection circuit 141 is provided between the power supply lines 25a and 25b on the downstream side of the connection / disconnection switch 32 and the ground part G. Similarly, the output voltage detection circuit The circuit 142 is provided between the power supply lines 26 a and 26 b on the downstream side of the connection / disconnection switch 33 and the ground portion G. The output voltage detection circuit 141 (142) connects the power supply line 25a (26a) and the ground portion G by the ground resistor 41a (42a) and between the power supply line 25b (26b) and the ground portion G. Are connected by a grounding resistor 41b (42b). Furthermore, potential measuring means 141a and 141b (142a and 142b) for measuring potentials Vpn11 and Vpn12 (Vpn21 and Vpn22) between both ends of the ground resistors 41a and 41b (42a and 42b) are provided.

  The potential detection unit 153 constituting the control unit 105 obtains detection signals of potential differences Vpn11 to Vpn22 at both ends of the ground resistors 41a to 42b by the potential measurement units 141a to 142b, amplifies them, and detects the potential differences Vpn11 to Vpn22. The value can be output to the potential abnormality determination unit 154 as a value. The potential abnormality determination unit 154 stores a predetermined threshold value Vth therein, and among the potential differences Vpn11 to Vpn22, the standby power supply line 26a connected to the open / close switch 33, The detected value of the potential difference Vpn21, Vpn22 on the 26b side is compared with the threshold value Vth. Of course, instead of the disconnection switch 33, when the disconnection switch 32 side is in the open state, the detected values of the potential differences Vpn11, Vpn12 on the power supply lines 25a, 25b side are compared with the threshold value Vth. . When the detection values of Vpn11 to Vpn22 are output as negative values, the absolute value may be compared with the threshold value Vth.

  When at least one of the detected values of the potential differences Vpn21 and Vpn22 on the standby power supply lines 26a and 26b is equal to or greater than the threshold value Vth, it is determined that the welding is abnormal, and that fact is displayed on the display unit 56. At the same time, the output from the power converter 31 is stopped, and an abnormality flag is set to make the charging impossible state. When the detected values of the potential differences Vpn21 and Vpn22 are less than the threshold value Vth, the normal state is determined, and the output from the power converter 31 is not stopped or the abnormality flag is not set.

  Further, by obtaining the difference between the potential differences Vpn11 and Vpn12 and the difference between the potential differences Vpn21 and Vpn22, the potential differences Vpn1 and Vpn2 between the high voltage lines 25a and 26a and the low voltage lines 25b and 26b can be easily obtained. By configuring the output voltage of the power converter 31 to be feedback controlled using the potential differences Vpn1 and Vpn2 while configuring in this way, it is possible to perform voltage control with higher accuracy.

  Furthermore, it is also possible to perform the detection of welding of the connection switches 32 and 33 by comparing the potential differences Vpn1 and Vpn2 obtained by the above configuration with the threshold value Vth.

  Even when configured as described above, it is possible to obtain the same operational effects as in the case of the first embodiment.

  Furthermore, the electric vehicle charging apparatus 101 according to the present embodiment includes branch lines 23a to 24b extending from the power converter 31 serving as the DC power output unit to the connection / disconnection switches 32 and 33, and the connection / disconnection switches 32 and 33. The power supply lines 25a to 26b reaching the charging connectors 34 and 35 are respectively composed of high voltage lines 25a and 26a and low voltage lines 25b and 26b, and the connection / disconnection switches 32 and 33 are provided on the high voltage lines 25a and 26a. In the case where DC power is output from the power converter 31, the branch line is formed by the high voltage side switch elements 32a and 33a and the low voltage side switch elements 32b and 33b provided in the low voltage lines 25b and 26b. Each of the high voltage lines 23a and 24a and the low voltage lines 23b and 24b constituting the portions 23a to 24b The potential abnormality determination unit 154 is configured such that the high voltage lines 25a and 26a and the low voltage line 25b constituting the power supply lines 25a to 26b on the downstream side of the connection / disconnection switch 33 in the disconnected state. , 26b, a potential abnormality is determined when at least one of the potential differences Vpn11 to Vpn22 between the potential and the reference potential is equal to or greater than a threshold value Vth.

  Even in such a configuration, when any one of the switch elements 32a to 33b constituting the connection / disconnection switches 32 and 33 is welded, any potential difference Vpn11 to Vpn22 becomes equal to or greater than the threshold value Vth, so that the potential can be easily set. It is possible to detect the welding by determining the abnormality.

  The specific configuration of each unit is not limited to the above-described embodiment.

  For example, each of the electric vehicle charging devices 1 and 101 of the first embodiment and the second embodiment includes the two charging connectors 34 and 35 and the connection / disconnection switch 32 connected to one of them is in a connected state (closed state). ), The connection / disconnection switch 33 connected to the other is in the disconnected state (open state), and the welding of the connection / disconnection switch 33 in the disconnected state is detected by determining the potential abnormality. It is also possible to detect the welding of a plurality of connection / disconnection switches 32 and 33 at the same time by determining the potential abnormality with both connection / disconnection switches 32 and 33 disconnected.

  In addition, the number of charging connectors 34 and 35 is not limited to two, and may be a large number of three or more. Even in such a case, the number of connecting / disconnecting switches 32 and 33 is increased and the same configuration is made. It is possible.

  Other configurations can be variously modified without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1,101 ... Electric vehicle charging device 5 ... Control means 22a ... Output line (high voltage line)
22b: Output line (low voltage line 23a, 24a ... branch line (high voltage line)
23b, 24b ... branch line (low voltage line)
25a, 26a ... Power supply line (high voltage line)
25b, 26b ... Power supply line (low voltage line)
31 ... DC power output unit (power converter)
32, 33 ... Connection / disconnection switch 32a, 33a ... High voltage side switch element 32b, 33b ... Low voltage side switch element 34, 35 ... Charging connector 41a, 41b, 42a, 42b ... Grounding resistance 43a, 43b ... Ground fault resistance 51 ... Ground fault current detection unit 52 ... Leakage abnormality determination unit 53, 153 ... Potential detection unit 54, 154 ... Potential abnormality determination unit G ... Grounding unit Vpn1, Vpn2, Vpn11, Vpn12, Vpn21, Vpn22 ... Potential difference Vth ... (potential difference) threshold

Claims (5)

A DC power output unit configured to enable output of DC power of a predetermined voltage based on energy obtained from an AC power source connected to the upstream side, and to stop output of this DC power;
A plurality of charging connectors for connecting to an electric vehicle;
A plurality of connecting / disconnecting switches connected to a branch line branched from the DC power output unit;
A power supply line for supplying power from these connecting / disconnecting switches to the charging connector;
A controller that operates the DC power output unit and selectively connects the connection / disconnection switch to supply DC power to a desired charging connector; and
The control means detects a potential in the power supply line downstream from each connection switch, and outputs a potential detection value, a potential detection unit,
A potential abnormality determination unit that determines potential abnormality based on a potential detection value by the potential detection unit;
An electric vehicle charging device configured to stop output of DC power from the DC power output unit when the potential abnormality determination unit determines that the potential is abnormal.   When the potential abnormality determination unit outputs DC power from the DC power output unit, the potential abnormality is determined when the potential of the power supply line downstream of the disconnection switch in the disconnected state is equal to or greater than a predetermined threshold. The charging device for an electric vehicle according to claim 1, wherein the charging device is configured to make a determination. The branch line from the DC power output unit to the connection / disconnection switch, and the power supply line from each connection / disconnection switch to the charging connector are each composed of a high voltage line and a low voltage line,
Each connecting / disconnecting switch is composed of a high voltage side switch element provided in the high voltage line and a low voltage side switch element provided in the low voltage line,
When direct current power is output from the direct current power output unit, each potential in the high voltage line and the low voltage line constituting the branch line is different from the reference potential,
The potential abnormality determining unit determines that the potential abnormality is present when a potential difference between a high voltage line and a low voltage line constituting a power supply line on the downstream side of the disconnected switch in a disconnected state is equal to or greater than the threshold value. The charging device for an electric vehicle according to claim 2, wherein the charging device is configured as follows.   4. The electricity according to claim 3, wherein a high voltage line and a low voltage line that constitute a power supply line downstream of the connection / disconnection switch are electrically connected to a grounding part via a grounding resistor. Car charger. A high voltage line and a low voltage line that constitute an output line from the DC power output unit to the connection / disconnection switch are electrically connected to the ground unit via a ground fault resistor, and While setting the resistance value of the resistor smaller than the resistance value of the ground resistance,
The control means includes a ground fault current detection unit that detects a current flowing through the ground fault resistance, and a ground fault abnormality determination unit that determines a ground fault abnormality based on a current detection value by the ground fault current detection unit. The charging device for an electric vehicle according to claim 4.

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