JP2014033558A - Power conversion device and charge/discharge system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To check, by a simple configuration, the conduction state of a power-feeding path between a device of a DC power supply source and a device of a DC power supply destination.SOLUTION: A switching circuit 5 converts an AC voltage of a power system 2 into a DC voltage in a state including a small-amplitude AC component (pulsating current). When a charge cable 8 of a charge/discharge device 1 is connected to an electric vehicle 4, the switching circuit 5 passes an AC current containing the AC component via capacitors C1 and C2 to the electric vehicle 4 side. The conduction state is checked by detecting the AC current by using a current sensor CS.

Description

  The present invention is a power conversion device that converts alternating current power supplied from a power system into direct current power, the power conversion for inspecting electrical connection in a non-contact manner with respect to a power supply line to a device that supplies direct current power. It relates to the device.

  An electric vehicle such as an electric vehicle is equipped with a storage battery, and in order to charge the storage battery, it is necessary to connect the charging device to the storage battery. When charging, if the electrical connection between the charging device and the storage battery is not performed correctly, there is a possibility of short circuit or electric shock, which is not preferable from the viewpoint of safety. Therefore, prior to charging, it is necessary to confirm that the energized state between the charging device and the storage battery is secured. This applies not only to storage batteries, but also to the energization between a DC power source and a device that is supplied with DC power from the DC power source, and prior to energizing the device, between the power source and the device. It is necessary to confirm that the energized state is secured.

  In the case of alternating current, by using a voltage detector, it is possible to inspect the energized state in a non-contact manner from the power cable covering. However, since direct current is used for charging a storage battery such as an electric vehicle, it is not possible to inspect the energized state in a non-contact manner as in the case of alternating current.

  On the other hand, Patent Document 1 discloses a voltage detection device that detects a live state of a DC train line. The voltage detector includes a fixed electrode electrically connected to the overhead wire, and a movable electrode connected to the fixed electrode by a wire and formed on the silicon substrate together with the fixed electrode. If the overhead wire is in a live line state, both electrodes are charged at the same potential, so that a repulsive force is generated between both electrodes, and the movable electrode receives this repulsive force and deforms the silicon substrate. By detecting at, it can be determined that the overhead line is a live line.

  On the other hand, Patent Document 2 discloses a system for monitoring a connection state of a charging cable before starting to charge an electric vehicle. In this system, an AC voltage of about 5V is generated from the AC voltage of the AC power source, and the AC voltage is applied to the charging cable, thereby detecting the AC current flowing in the charging cable and the charging path formed in the electric vehicle. Check the power status of the charging cable.

JP 2007-205978 A (published August 16, 2007) Japanese Patent No. 3214045 (issued on October 2, 2001)

  The voltage detection device described in Patent Document 1 has an inconvenience that the configuration of the device becomes complicated due to the inspection with an ultrahigh voltage.

  In the system described in Patent Document 2, an alternating current is detected, so that a conventional voltage detector can be used. However, a configuration such as a transformer for generating an alternating current is required, which increases the cost of the system. In addition, it is necessary to control a relay for switching between an AC circuit and a DC circuit, resulting in complicated control.

  The present invention has been made in view of the above problems, and an object of the present invention is to inspect the energization state of a power feeding path between a DC power supply source and a DC power supply destination device with a simple configuration. .

  In order to solve the above problems, a power conversion device according to the present invention converts a AC voltage supplied from a power system into a DC voltage, a DC voltage from the voltage conversion circuit and the voltage conversion circuit. An inspection device for inspecting a current-carrying state of the current path by detecting a current flowing in a current path with a given device in a non-contact manner, and the voltage conversion circuit outputs a DC voltage including a pulsating current It is characterized by that.

  In the above configuration, a DC voltage including a pulsating current is output from the AC voltage of the power system by the voltage conversion circuit. At this time, the AC component based on the pulsating current is also included in the current flowing in the current path between the voltage conversion circuit and the device. Therefore, when the current flowing through the current path is detected by the tester, the current path is energized.

  Thus, since the alternating current flowing through the current path is obtained by the voltage conversion circuit, a dedicated configuration for generating such alternating current is not necessary. Therefore, complication of the configuration of the power conversion device can be avoided.

  In the power conversion device, the voltage conversion circuit includes an output capacitor that outputs DC power, a first operation of supplying AC power from the power system to the output capacitor, and power stored in the output capacitor. It is preferable to alternately repeat the second operation of converting AC to AC power and supplying the AC power to the power system. Moreover, it is preferable that the voltage conversion circuit repeats the first operation and the second operation alternately based on the frequency of the power system.

  In the above configuration, when the device is a device that operates with direct current power and is supplied with direct current power from another direct current power source, the voltage conversion circuit is connected to the alternating current voltage of the power system into the direct current voltage. Since no current can be obtained, no alternating current can be obtained. In such a case, the voltage conversion circuit repeats the first operation and the second operation, so that fluctuating power can be obtained. Therefore, this varying current can be detected by the tester.

  Further, the voltage conversion circuit alternately repeats the first operation and the second operation based on the frequency of the power system, so that a current that varies according to the frequency of the power system can be obtained.

  In the power conversion device, it is preferable that at least one of a solar battery and a storage battery system is connected to a power supply line through which the voltage conversion circuit supplies DC power.

  In the above configuration, since a solar battery and a storage battery system are used as the DC power source described above, it is possible to effectively use obtaining a current that fluctuates as described above.

  A charging / discharging system according to the present invention is a charging / discharging system including an electric vehicle and a charging / discharging device that charges / discharges the electric vehicle. The voltage conversion circuit in the power conversion device is provided in the charge / discharge device, the inspection device in the power conversion device is provided in the electric vehicle, and the charge / discharge device is an output stage of the voltage conversion circuit. And a switch for short-circuiting both ends of the capacitor at the time of charging.

  In the above configuration, prior to charging of the storage battery, only the AC component is added to the current including the AC component output from the voltage conversion circuit by the capacitor. Thereby, this alternating current can be detected by the tester. Moreover, at the time of charge of a storage battery, the output voltage from a voltage conversion circuit can be charged to a storage battery via a switch by short-circuiting the both ends of a capacitor | condenser with a switch.

  The power conversion device according to the present invention is configured as described above, so that the energization state of the power feeding path between the DC power supply source and the DC power supply destination device can be inspected with a simple configuration. There is an effect.

It is a circuit diagram which shows the structure of the charging / discharging system which concerns on Embodiment 1 of this invention. It is a figure which shows the change of the output voltage of the switching circuit provided in the charging / discharging apparatus in the said charging / discharging system. It is a timing chart which shows the operation | movement at the time of charge of the said charging / discharging apparatus. It is a timing chart which shows the operation | movement at the time of the discharge of the said charging / discharging apparatus. It is a flowchart which shows the procedure of operation | movement of the said charging / discharging system. It is a timing chart which shows the operation | movement at the time of discharge in. It is a circuit diagram which shows the structure of the charging / discharging system which concerns on Embodiment 2 of this invention.

[Embodiment 1]
An embodiment according to the present invention will be described below with reference to FIGS.

[Configuration of charge / discharge system]
FIG. 1 is a block diagram showing a configuration of a discharge system 11 according to the present embodiment.

  As shown in FIG. 1, the charge / discharge system 11 includes a charge / discharge device 1, a power system 2, a line filter 3, and an electric vehicle 4.

<Configuration of power system and line filter>
The electric power system 2 outputs AC voltages V1 and V2 whose phases are different from each other by 90 °.

  The line filter 3 includes line bypass capacitors C01 and C02 and normal mode choke coils L1 and L2.

  The line bypass capacitors C01 and C02 are connected in series between the two output lines of the power system 2, and are connected to the ground line between the line bypass capacitors C01 and C02. These line bypass capacitors C01 and C02 are provided to bypass common mode noise to the ground line. Normal mode choke coils L1 and L2 are respectively connected to two output lines of power system 2, and are inductors that absorb normal mode noise.

  A voltage sensor VS1 is provided at the output terminal of the normal mode choke coil L1. The voltage sensor VS1 measures the voltage at the output terminal of the normal mode choke coil L1. On the other hand, a voltage sensor VS2 is provided at the output terminal of the normal mode choke coil L2. The voltage sensor VS2 measures the voltage at the output terminal of the normal mode choke coil L2.

<Configuration of charge / discharge device>
The charging / discharging device 1 (power conversion device) includes a switching circuit 5, a control device 6, a charging connector 7, a charging cable 8, capacitors C1 and C2, and switches SW1 and SW2.

<Configuration of charging connector and charging cable>
The charging connector 7 is a connector for connecting the charging cable 8 to the charging port of the electric vehicle 4, and is provided at the tip of the charging cable 8. The charging connector 7 is configured to have an electrode arrangement according to the charging method.

  The charging cable 8 is a cable for performing communication and power transmission between the charging / discharging device 1 and the electric vehicle 4, and is configured by housing the communication line and the power line in the cable sheath. The charging cable 8 is normally connected to the charging / discharging device 1 so as not to be disconnected, and is configured as a part of the charging / discharging device 1.

<Configuration of switching circuit>
FIG. 2 is a diagram illustrating a change in the output voltage of the switching circuit 5.

  The switching circuit 5 (voltage conversion circuit) is a bidirectional inverter for converting AC power from the power system 2 into DC power and converting DC power discharged from the storage battery 9 of the electric vehicle 4 into AC power. is there. The switching circuit 5 includes switching elements S1 to S4, diodes D1 to D4, amplifiers A1 to A4, and a capacitor C3 in order to perform the above power conversion.

  The switching elements S1 to S4 are configured by power MOSFETs or IGBTs (Insulated Gate Bipolar Transistors). Alternatively, the switching elements S1 to S4 may be field effect transistors (GaN transistors) having a GaN (gallium nitride) layer.

  The switching element S1 has an output terminal connected to the output terminal of the normal mode choke coil L2, and an input terminal connected to one end of the capacitor C3. The switching element S2 has an output terminal connected to the other end of the capacitor C3, and an input terminal connected to the output terminal of the normal mode choke coil L2. The switching element S3 has an output terminal connected to the output terminal of the normal mode choke coil L1, and an input terminal connected to one end of the capacitor C3. The switching element S4 has an output terminal connected to the other end of the capacitor C3, and an input terminal connected to the output terminal of the normal mode choke coil L1.

  Capacitor C3 (output capacitor) is a smoothing capacitor provided to smooth the voltage obtained by rectifying the AC voltage by switching elements S1 to S4. The capacitor C3 has a capacity of about 1 mF.

  A voltage sensor VS3 is provided at both ends of the capacitor C3. The voltage sensor VS3 measures the voltage V3 across the capacitor C3, that is, the output voltage of the charging / discharging device 1.

  The amplifiers A1 to A4 are circuits that amplify the control voltage input to the control terminals of the switching elements S1 to S4. The control voltage input to the amplifiers A1 to A4 is output from the control device 6.

  The diodes D1 to D4 are connected between the input / output terminals of the switching elements S1 to S4, respectively. These diodes D1 to D4 are provided to prevent the flow of current in the reverse direction in the switching elements S1 to S4.

  The switching circuit 5 configured as described above converts the AC power supplied from the power system 2 to DC, but as shown in FIG. 2, it is completely so that an AC component (pulsating flow) with a small amplitude remains. Does not turn into direct current. The magnitude of the amplitude of the pulsating flow is preferably about 5% of the DC voltage, for example, about 20V with respect to the DC voltage of 400V.

  Note that the switching circuit 5 performs rectification and step-up at the time of AC-DC conversion so as to match the voltage of the storage battery 9 and operates in both directions (AC-DC conversion and DC-AC conversion). S1 to S4 are necessary.

<Configuration of switch and capacitor>
The switch SW1 is connected between one end of the capacitor C3 and the charging connector 4 (one (positive side) power line in the charging cable). The switch SW2 is connected between one end of the capacitor C3 and the charging connector 4 (the other (negative side) power line in the charging cable). These switches SW1 and SW2 are switches that open and close between the capacitor C3 and the charging connector 4, and short-circuit both ends of the capacitors C1 and C2, respectively.

  The capacitor C1 is provided in parallel with the switch SW1 at the output stage of the switching circuit 5, and is connected to both ends of the switch SW1. The capacitor C2 is provided in parallel with the switch SW2 at the output stage of the switching circuit 5, and is connected to both ends of the switch SW2.

  The capacitance values of the capacitors C1 and C2 can be set independently. If these capacitance values are too large, a large alternating current flows before the switches SW1 and SW2 are turned on. Therefore, there is a risk of electric shock when the charging connector 4 is touched. For example, for a DC voltage of 400 V, the capacitors C1 and C2 are set to a capacitance value of about 10 μF.

<Control device configuration>
The control device 6 communicates with the electric vehicle 4 to control charging / discharging of the storage battery 9 of the electric vehicle 4 and to control operations of the switching circuit 5 and the switches SW1 and SW2. The control device 6 includes a charge / discharge control unit 61, a switching circuit control unit 62, and a switch control unit 63 in order to perform the above control.

  The charge / discharge control unit 61 controls charging by communication with the electric vehicle 4. Specifically, the charge / discharge control unit 61 gives the electric vehicle 4 the capabilities (maximum output voltage, maximum output current, etc.) of the charge / discharge device 1.

  The charging / discharging control unit 61 receives the charging permission and the instruction current value from the electric vehicle 4 during the charging operation of the storage battery 9 and supplies the current of the instructed current value to the switching circuit control unit 62 of the switching circuit 5. A control instruction for controlling the operation is given. Further, as will be described later, in a state where the charging cable 8 is not connected to the electric vehicle 4, the switching circuit control unit 62 controls the switching circuit 5 so as to repeat the charging / discharging operation for the capacitor C3. However, the charging / discharging control unit 61 controls the voltage of V3 to be 400 ± 20 V until the switches SW1 and SW2 are connected. After the switches SW1 and SW2 are connected, either the charging or discharging of the storage battery 9 is performed. Control of whether to perform and control of charging / discharging current are performed. For this reason, the charging / discharging control part 61 notifies the connection to the electric vehicle 4 of the charging connector 7 to the switching circuit control part 62 by giving a connection signal.

  The charge / discharge control unit 61 gives a control instruction to the switch control unit 63 so that the switch control unit 63 turns off the switches SW1 and SW2 when the charge / discharge of the storage battery 9 is completed. For this reason, the charging / discharging control part 61 notifies the switch control part 63 that the storage battery 9 complete | finished charging / discharging operation | movement by giving a charging / discharging completion | finish signal.

  The switching circuit control unit 62 controls the switching operation of the switching elements S1 to S4 so as to convert the AC voltage from the power system 2 into a DC voltage. Further, the switching circuit control unit 62 controls the switching operation of the switching elements S1 to S4 so as to convert the DC voltage discharged from the storage battery 9 of the electric vehicle 4 into an AC voltage.

  The switching circuit control unit 62 performs an operation for supplying AC power from the power system 2 to the capacitor C3 (first operation) and an operation for supplying the power stored in the capacitor C3 to the power system 2 (second operation). The switching operations of the switching elements S1 to S4 are controlled so as to be repeated alternately. This repeated operation is performed, for example, at the frequency (cycle) of the power system 2. For example, the above repeating operation is performed at a cycle of 20 ms when the power system 2 is 50 Hz, and is performed at a cycle of 16.7 ms when the power system 2 is 60 Hz. The switching circuit control unit 62 receives the connection signal from the charge / discharge control unit 61, repeats the above operation, and stands by in preparation for the charge / discharge operation of the storage battery 9.

  The switching circuit control unit 62 performs the above control operation in conjunction with the charge / discharge operation of the storage battery 9 based on the control instruction from the charge / discharge control unit 61.

  The switch control unit 63 controls the opening / closing operation of the switches SW1 and SW2. Specifically, the switch control unit 63 controls the switches SW1 and SW2 to be turned on when a current sensor CS (described later) provided in the electric vehicle 4 detects a current. In addition, when the switch control unit 63 recognizes that charging / discharging of the storage battery 9 has been completed based on the input of the charging / discharging end signal from the charging / discharging control unit 61, the switch control unit 63 controls the switches SW1, SW2 to be turned off.

[Configuration of electric vehicle]
The electric vehicle 4 (electric vehicle) includes a storage battery 9, a current sensor CS, and a capacitor C4.

  The storage battery 9 is a large-capacity storage battery that stores electric power to be supplied to an electric motor (not shown) provided in the electric vehicle 4. The storage battery 9 is constituted by, for example, a lithium ion battery.

  The current sensor CS (inspector) is a detector that detects a current flowing through the storage battery 9 in an electrically non-contact manner with a circuit through which the current flows. As the current sensor CS, a sensor provided with a current transformer, a sensor that magnetically detects a current using a Hall element, or the like is used.

  Although the current sensor CS is provided in the electric vehicle 4, the switch control unit 63 is a detector for controlling ON / OFF of the switches SW1 and SW2, and is connected to the switch control unit 63. Therefore, it is assumed to be a constituent element of the charge / discharge device 1.

  The capacitor C4 is a capacitor provided in the electric vehicle 4 for flowing an alternating current flowing through the capacitors C1 and C2 and smoothing the charging current of the storage battery 9 into a direct current.

  Although not shown, the electric vehicle 4 includes a contactor (electromagnetic contactor) that opens and closes a current path between the charging port and the storage battery 9. Moreover, although not shown in figure, the electric vehicle 4 has the storage battery management part which manages the state of the storage battery 9. FIG. In particular, the storage battery management unit controls charging of the storage battery 9 by communicating with the charge / discharge control unit 61 described above. For this purpose, the storage battery management unit gives the above-described charging permission, instruction current value, storage battery information, and the like to the charge / discharge control unit 61.

[Operation of charge / discharge system]
Then, the operation | movement of the charging / discharging system 11 comprised as mentioned above is demonstrated.

  FIG. 3 is a timing chart showing an operation during charging of the charging / discharging device 1. FIG. 4 is a timing chart showing the operation of the charging / discharging device 1 during discharging. FIG. 5 is a flowchart showing an operation procedure of the charge / discharge system 11.

<Operation of switching circuit during charging (charging sequence)>
When the storage circuit 9 is charged, the switching circuit 5 is controlled by the switching circuit control unit 62 as shown in FIG.

  When the value of AC voltage V1 of power system 2 is positive (V1> 0), switching element S1 maintains the OFF state. In this state, first, the switching elements S2 and S3 are turned off, and the switching element S4 is turned on. Thereby, current flows from the normal mode choke coil L1 to the switching element S4, the diode D2, and the normal mode choke coil L2, and energy is stored in the normal mode choke coils L1 and L2. Thereafter, when the switching element S4 is turned OFF and the switching elements S2 and S3 are turned ON, the voltage is boosted from the AC voltage through the path of the normal mode choke coil L1, the switching element S3, the capacitor C3, the switching element S2, and the normal mode choke coil L2. A voltage is generated and the electric charge of the capacitor C3 is retained. By repeating such an operation alternately, the voltage across the capacitor C3 reaches the voltage V3 output to the storage battery 9.

  On the other hand, when the value of the AC voltage V2 of the power system 2 is positive (V2> 0), the switching element S3 maintains the OFF state. In this state, first, the switching elements S1 and S4 are turned off, and the switching element S2 is turned on. Then, a current flows from normal mode choke coil L2 to switching element S2, diode D4, and normal mode choke coil L1, and energy is stored in normal mode choke coils L1 and L2. Thereafter, when the switching element S2 is turned off and the switching elements S1 and S4 are turned on, a current flows through the path of the normal mode choke coil L2, the switching element S1, the capacitor C3, the switching element S4, and the normal mode choke coil L1. Thereby, the electric charge of the capacitor C3 is held. By repeating such an operation alternately, the voltage across the capacitor C3 reaches the voltage V3 output to the storage battery 9.

<Operation of switching circuit during discharge (discharge sequence)>
When the storage circuit 9 is discharged, the switching circuit 5 is controlled by the switching circuit control unit 62 as shown in FIG. Thereby, the switching elements S1 to S4 are turned on when the gate signals Vs1 to Vs4 are at the “1” level, respectively, and are turned off when the gate signals Vs1 to Vs4 are at the “0” level.

  When obtaining a positive AC voltage, a part of the ON time of the switching elements S2 and S3 overlaps, and when one of the switching elements S1 and S4 is turned ON, the other is turned OFF. On the other hand, when obtaining a negative AC voltage, a part of the ON time of the switching elements S1 and S4 overlaps, and when one of the switching elements S2 and S3 is ON, the other is OFF.

  At this time, as shown in FIG. 4, the voltage obtained intermittently by the switching operation by the switching elements S1 to S4 is smoothed by the capacitor C3, so that an AC voltage Vinv of 200 V is output.

<Operation of charging / discharging device during charging / discharging>
When charging / discharging the storage battery 9, the charging / discharging apparatus 1 operate | moves according to the procedure of the flowchart shown in FIG.

  First, the switching circuit 5 operates in a state where the charging cable 8 is not connected to the electric vehicle 4 (step S1), and the capacitor C3 is charged / discharged (step S2). At this time, in the switching circuit 5, the operation of supplying the AC power from the power system 2 to the capacitor C3 and the operation of supplying the power stored in the capacitor C3 to the power system 2 are alternately repeated. S1 to S4 perform a switching operation.

  When the charging cable 8 is not connected to the electric vehicle 4, that is, when there is no load that consumes power, the power is stored in the capacitor C3 (power purchase), and the power stored in the capacitor C3 is supplied to the power system 2. Repeat what you do (power sale). Thereby, it can avoid that the place of electric power disappears by continuing supply of electric power from the electric power grid | system 2. FIG.

  Next, it is determined whether or not the charging cable 8 is connected to the electric vehicle 4 (step S3). Here, when the charging cable 8 is connected to the electric vehicle 4, it is determined whether or not a current is detected by the current sensor CS (step S4).

  In a state where the charging cable 8 is connected, the switches SW1 and SW2 are OFF. For this reason, the current from the switching circuit 5 flows through the current path formed by the capacitor C1, the charging cable 8, the capacitor C4 in the electric vehicle 4, the charging cable 8, and the capacitor C2, and returns to the switching circuit 5. Thereby, an alternating current due to a pulsating flow as shown in FIG. 2 flows through the capacitors C1 and C2 and flows into the electric vehicle 4. Therefore, if no abnormality occurs in the current path, the alternating current flows correctly and is detected by the current sensor CS.

  When the current is detected as described above, the switches SW1 and SW2 are turned on (step S5), and the storage battery 9 is charged or discharged (step S6). In this state, a current flows between the switching circuit 5 and the electric vehicle 4 via the switches SW1 and SW2.

  When charging the storage battery 9, the switching circuit 5 operates as described above (charging sequence). When discharging the storage battery 9, the switching circuit 5 operates as described above (discharge sequence).

  Eventually, when charging or discharging of the storage battery 9 is completed (step S7), the switches SW1 and SW2 are turned off (step S8). Then, from this state, the operation of the switching circuit 5 is stopped (step S9), and the process is finished.

[Effects of charge / discharge system]
As described above, the charging / discharging system 11 detects the alternating current by the current sensor CS in the electric vehicle 4 by causing the alternating current of the pulsating current to flow from the switching circuit 5 to the electric vehicle 4 via the capacitors C1 and C2. be able to. Thereby, since the electricity supply state of the electric power feeding path formed between the charging connector 7 charging cable 8 and the charger 9 is test | inspected, the storage battery 9 can be charged / discharged safely.

  In addition, since an alternating current flowing through the electric vehicle 4 is obtained by the switching circuit 5, a dedicated configuration for generating such an alternating current is not necessary. Therefore, complication of the configuration of the charge / discharge system 11 can be avoided. Moreover, the AC component (pulsating flow) superimposed on the voltage applied to the electric vehicle 4 has an amplitude that does not affect the charging of the storage battery 9 and that an AC current of a level that can be detected by the current sensor CS is obtained. Set small. Therefore, the storage battery 9 can be charged without any trouble.

  Further, since no power is purchased from the power system 2 at the time of discharging, an AC current for current detection cannot be obtained based on the AC power supplied from the power system 2. In this case, by performing the operation of step S2 described above also between steps S3 and S4, it is possible to flow a fluctuating current through the above-described current path. Thereby, even at the time of discharge, an energized state can be inspected in advance.

  In the above example, charging or discharging of the storage battery 9 of the electric vehicle 4 has been described. However, in the charging / discharging system 11, for example, an energization state at the time of connection of the DC device 10 that operates with DC power can also be inspected. .

  As shown in FIG. 1, DC equipment 10 such as a DC home appliance is supplied with DC power from both ends of a capacitor C3. In a state where the DC device 10 is connected to the capacitor C <b> 3, a current including an AC component flows from the switching circuit 5. Thereby, in a current path formed between the switching circuit 5 and the DC device 01, when a sensor similar to the current sensor CS is used, a current flowing through the current path can be detected.

[Realization of control device]
The block of the control device 6 in the charge / discharge device 1 is realized by software (control program) using a CPU as follows. Or each said block may be comprised by a hardware logic, and may be implement | achieved by the process by the program using DSP (Digital Signal Processor).

  The program code (execution format program, intermediate code program, source program) of the above software may be recorded on a recording medium recorded so as to be readable by a computer. The object of the present invention can also be achieved by supplying the recording medium to the charging / discharging device 1 and reading and executing the program code recorded on the recording medium by the CPU.

  Examples of the recording medium include magnetic tapes such as magnetic tapes and cassette tapes, magnetic disks such as floppy (registered trademark) disks / hard disks, and optical disks such as CD-ROM / MO / MD / BD / DVD / CD-R. Can be used, a card system such as an IC card (including a memory card) / optical card, or a semiconductor memory system such as a mask ROM / EPROM / EEPROM (registered trademark) / flash ROM.

  Further, the charging / discharging device 1 may be configured to be connectable to a communication network, and the program code may be supplied via the communication network. The communication network is not particularly limited. For example, the Internet, intranet, extranet, LAN, ISDN, VAN, CATV communication network, virtual private network, telephone line network, mobile communication network, satellite communication. A net or the like is available. Further, the transmission medium constituting the communication network is not particularly limited. For example, even in the case of wired such as IEEE 1394, USB, power line carrier, cable TV line, telephone line, ADSL line, etc., infrared rays such as IrDA and remote control, Bluetooth ( (Registered trademark), 802.11 wireless, HDR, mobile phone network, satellite line, terrestrial digital network, and the like can also be used. The present invention can also be realized in the form of a computer data signal embedded in a carrier wave in which the program code is embodied by electronic transmission.

[Embodiment 2]
Another embodiment according to the present invention will be described below with reference to FIG.

  FIG. 6 is a block diagram showing a configuration of the charge / discharge system 12 according to the present embodiment.

  In the present embodiment, components having functions equivalent to those of the components in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

[Configuration of charge / discharge system]
As shown in FIG. 6, the charge / discharge system 12 includes a charge / discharge device 1, a power system 2, a line filter 3, and an electric vehicle 4, similar to the charge / discharge system 11 described above. The charge / discharge system 12 includes a solar cell 13, a DC / DC converter (indicated by “DC / DC” in the figure) 14, a storage battery system 15, and a DC device 16. The DC device 16 is the same device as the DC device 10 described above.

  In this charging / discharging system 12, the DC power obtained by the solar cell 13 is stored in the storage battery system 15, and the power is supplied to the DC equipment 16 and the electric vehicle 4, or converted into AC power for various types of houses and the like. Or supply to AC equipment. The storage battery system 15 may store DC power obtained from the power system 2 via the switching circuit 5 of the charging / discharging device 1, or supply the stored DC power to the DC device 16 or the electric vehicle 4. Good. The DC / DC converter 14 converts the high voltage output from the solar battery 13 into a low voltage and gives it to the storage battery system 15.

[Operation of charge / discharge system]
In the charge / discharge system 12 configured as described above, the switching circuit 5 operates basically in the same manner as the charge / discharge system 11 described above, and operates according to the flowchart of FIG. However, when at least one of the solar battery 13 and the storage battery system 14 is operating, the charge / discharge system 12 is in the flowchart shown in FIG. The operation of step S2 is performed.

  In the above case, since power is not purchased from the power system 2, the voltage of the power supply line connected to both ends of the capacitor C3 or both ends of the capacitor C3 does not vary. In this case, the switching circuit 5 alternately repeats the operation of supplying the AC power from the power system 2 to the capacitor C3 and the operation of supplying the power stored in the capacitor C3 to the power system 2. Thereby, a fluctuating current flows in a current path between charging / discharging device 1 and electric vehicle 4 or a current path between charging / discharging device 1 and DC device 16. Therefore, an energization inspection between the charge / discharge device 1 and the electric vehicle 4 or an energization inspection between the charge / discharge device 1 and the DC device 16 can be performed.

[Effects of charge / discharge system]
As described above, similarly to the charge / discharge system 11, the charge / discharge system 12 causes a pulsating alternating current to flow from the switching circuit 5 to the electric vehicle 4 via the capacitors C <b> 1 and C <b> 2. Thereby, the alternating current can be detected by the current sensor CS in the electric vehicle 4. Therefore, since the energization state of the charging cable 8 is inspected, the storage battery 9 can be charged and discharged safely. In addition, since a dedicated configuration for generating an alternating current is not necessary, the configuration of the charge / discharge system 12 can be prevented from becoming complicated.

  The switching circuit 5 is operated not only when the storage battery 9 is discharged but also when it is not necessary to purchase power from the power system 2 in which at least one of the solar battery 13 and the storage battery system 15 is operating as described above. Thus, buying and selling power for the power system 2 is repeated in small increments. Thereby, since the current which fluctuates flows in the above-mentioned current path, it is possible to inspect the energization state between the charge / discharge device 1 and the electric vehicle 4 or the energization state between the charge / discharge device 1 and the DC device 16. it can.

[Additional Notes]
In the first and second embodiments, charging of the electric vehicle 4 has been mainly described. However, the present invention is naturally applicable to vehicles other than the electric vehicle 4. Examples of the electric vehicle include a vehicle equipped with a storage battery, and include general vehicles such as electric motorcycles and electric tricycles, industrial vehicles such as electric forklifts, and welfare vehicles such as electric wheelchairs.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims. That is, embodiments obtained by combining technical means appropriately modified within the scope of the claims are also included in the technical scope of the present invention.

  The power conversion device according to the present invention inspects energization of the current path by detecting an alternating current obtained by using a pulsating flow obtained from an alternating voltage from the power system. It can be suitably used for energization inspection of the connection path between them.

1 Charging / discharging device (power converter)
2 Power system 4 Electric vehicle (electric vehicle)
5 Switching circuit (voltage conversion circuit)
6 control device 7 charging connector 8 charging cable 9 storage battery 10 DC device 11 charge / discharge system 12 charge / discharge system 13 solar cell 15 storage battery system 16 DC device 61 charge / discharge control unit 62 switching circuit control unit 63 switch control unit C1, C2 capacitor C3 Capacitor (output capacitor)
CS current sensor (inspector)
SW1, SW2 switch

Claims (5)

A voltage conversion circuit that converts AC voltage supplied from the power system into DC voltage;
An inspection device for inspecting the energization state of the current path by detecting a current flowing in a current path between the voltage conversion circuit and a device to which a DC voltage is applied from the voltage conversion circuit;
The voltage conversion circuit outputs a DC voltage including a pulsating current.   The voltage conversion circuit includes an output capacitor that outputs DC power, a first operation for supplying AC power from the power system to the output capacitor, and converts power stored in the output capacitor into AC power. The power converter according to claim 1, wherein the second operation supplied to the power system is alternately repeated.   The power conversion device according to claim 2, wherein the voltage conversion circuit alternately repeats the first operation and the second operation based on a frequency of the power system.   The power converter according to claim 2 or 3, wherein at least one of a solar battery and a storage battery system is connected to a power supply line through which the voltage conversion circuit supplies DC power. A charge / discharge system comprising an electric vehicle including a storage battery, and a charge / discharge device for charging / discharging the electric vehicle,
The power converter according to any one of claims 1 to 4 is provided as the charge / discharge device,
The voltage conversion circuit in the power conversion device is provided in the charge / discharge device, the inspection device in the power conversion device is provided in the electric vehicle,
The charging / discharging device includes a capacitor provided at an output stage of the voltage conversion circuit, and a switch that short-circuits both ends of the capacitor during charging.

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