JP2017123739A - Bidirectional power conversion device, computer program and method of controlling bidirectional power conversion device - Google Patents

Abstract

A bidirectional power converter, a computer program, and a control method for the bidirectional power converter capable of preventing an inrush current without providing an inrush current prevention circuit. A voltage acquisition unit that acquires a voltage of a power storage device connected to a DC / DC conversion unit through an electric circuit having an opening / closing unit, and an AC / DC to convert alternating current into direct current when the opening / closing unit is in an open state. A control unit that controls the conversion unit and the DC / DC conversion unit, and a voltage detection that detects the voltage of the capacitor when the control unit controls the AC / DC conversion unit and the DC / DC conversion unit to convert alternating current into direct current. And a determination unit that determines whether or not the detected voltage of the capacitor and the voltage of the power storage device satisfy a required condition, and when the control unit determines that the condition is satisfied, the direct current of the power storage device is changed to an alternating current. The AC / DC conversion unit and the DC / DC conversion unit are controlled so as to convert the signal to DC. [Selection] Figure 1

Description

  The present invention relates to a bidirectional power converter that converts power to both, a computer program for controlling the bidirectional power converter, and a control method for the bidirectional power converter.

  A plug-in hybrid electric vehicle (PHEV) and an electric vehicle (PHEV) that is equipped with a power conversion device that converts alternating current supplied from a commercial power source into direct current, and that is charged by the direct current converted by the power conversion device. Vehicles such as EV (Electric Vehicle) are widely used.

  In recent years, it is expected that a battery mounted on a vehicle such as a plug-in hybrid vehicle or an electric vehicle is used as a power source at the time of disaster or emergency. In order to use a battery as a power source, it is necessary not only to convert alternating current into direct current but also to convert direct current into alternating current.

  For example, a bidirectional converter having a two-stage configuration of an AC / DC conversion unit and a DC / DC conversion unit and capable of converting alternating current into direct current and direct current into alternating current is disclosed (see Patent Document 1). . This bidirectional converter has a smoothing capacitor for smoothing direct current between the AC / DC conversion unit and the DC / DC conversion unit and between the DC / DC conversion unit and the direct current side terminal to which the battery is connected. Is connected.

JP 2010-178666 A

  However, in the bidirectional converter of Patent Document 1, when converting direct current to alternating current using an in-vehicle battery as a power source, a steep current flows to charge the smoothing capacitor, and the operation of converting direct current to alternating current is performed. When started, an excessive inrush current flows from the battery to the bidirectional converter, which may damage the electronic components and contacts in the bidirectional converter. In order to reduce the inrush current, it is necessary to provide an inrush current prevention circuit constituted by a resistor or the like.

  The present invention has been made in view of such circumstances, and a bidirectional power converter capable of preventing an inrush current without providing an inrush current prevention circuit, and for controlling the bidirectional power converter. It is an object to provide a computer program and a control method for the bidirectional power converter.

  A bidirectional power converter according to an embodiment of the present invention includes an AC / DC converter that converts AC and DC in both directions, and a DC / DC that is connected to the AC / DC converter and converts DC in both directions. A bidirectional power conversion device comprising a DC conversion unit and a capacitor for smoothing the direct current converted by the DC / DC conversion unit, which converts alternating current into direct current and direct current into alternating current, and through an electric circuit having an open / close unit A voltage acquisition unit for acquiring a voltage of an electricity storage device connected to the DC / DC conversion unit, and the AC / DC conversion unit and the DC / DC conversion unit to convert alternating current into direct current when the open / close unit is in an open state. A control unit that controls the capacitor, a voltage detection unit that detects the voltage of the capacitor when the control unit controls the AC / DC conversion unit and the DC / DC conversion unit to convert alternating current into direct current, and the voltage The capacity detected by the detection unit And a determination unit that determines whether or not the voltage of the power storage device acquired by the voltage acquisition unit satisfies a required condition, and the control unit determines that the condition is satisfied by the determination unit In this case, the AC / DC conversion unit and the DC / DC conversion unit are controlled to convert direct current of the power storage device into alternating current.

  A computer program according to an embodiment of the present invention includes a computer that has an AC / DC converter that converts AC and DC bidirectionally, and a DC / DC that is connected to the AC / DC converter and converts DC directly. A computer program for controlling a bidirectional power converter that includes a DC converter and a capacitor that smoothes the direct current converted by the DC / DC converter, and converts alternating current into direct current and direct current into alternating current, A voltage acquisition unit that acquires a voltage of a power storage device connected to the DC / DC conversion unit via an electric circuit having an opening / closing unit, and the AC to convert alternating current into direct current when the opening / closing unit is open. A control unit that controls the DC / DC conversion unit and the DC / DC conversion unit, and the capacity when the AC / DC conversion unit and the DC / DC conversion unit are controlled to convert alternating current into direct current. The voltage of the power storage device and the voltage of the power storage device function as a determination unit that determines whether or not a required condition is satisfied, and when the control unit determines that the condition is satisfied, the direct current of the power storage device is changed to an alternating current. The AC / DC converter and the DC / DC converter are controlled to perform conversion.

  A control method for a bidirectional power converter according to an embodiment of the present invention includes an AC / DC converter that converts AC and DC in both directions, and a DC that is connected to the AC / DC converter and converts DC in both directions. A bidirectional power converter control method comprising: a DC / DC converter that performs conversion; and a capacitor that smoothes the direct current converted by the DC / DC converter, and converts alternating current into direct current and direct current into alternating current. The AC / DC conversion unit is configured to acquire a voltage of an electric storage device connected to the DC / DC conversion unit via an electric circuit having a unit, and to convert alternating current into direct current with the open / close unit open. When the control unit controls the DC / DC conversion unit and the AC / DC conversion unit and the DC / DC conversion unit are controlled to convert alternating current into direct current, the voltage detection unit detects the voltage of the capacitor. The detected electric power of the capacitor When the determination unit determines whether or not the acquired voltage of the power storage device satisfies a required condition, and the control unit determines that the condition is satisfied, the direct current of the power storage device is converted into an alternating current. The AC / DC converter and the DC / DC converter are controlled accordingly.

  According to the present invention, an inrush current can be prevented without providing an inrush current prevention circuit.

It is explanatory drawing which shows an example of the circuit structure of the bidirectional | two-way power converter device of this Embodiment. It is explanatory drawing which shows an example of the conditions of the discharge operation start of the bidirectional | two-way power converter device of this Embodiment. It is explanatory drawing which shows an example of the peripheral circuit containing a contactor unit. It is a flowchart which shows an example of the control method of the bidirectional | two-way power converter device of this Embodiment.

[Description of Embodiment of Present Invention]
A bidirectional power converter according to an embodiment of the present invention includes an AC / DC converter that converts AC and DC in both directions, and a DC / DC that is connected to the AC / DC converter and converts DC in both directions. A bidirectional power conversion device comprising a DC conversion unit and a capacitor for smoothing the direct current converted by the DC / DC conversion unit, which converts alternating current into direct current and direct current into alternating current, and through an electric circuit having an open / close unit A voltage acquisition unit for acquiring a voltage of an electricity storage device connected to the DC / DC conversion unit, and the AC / DC conversion unit and the DC / DC conversion unit to convert alternating current into direct current when the open / close unit is in an open state. A control unit that controls the capacitor, a voltage detection unit that detects the voltage of the capacitor when the control unit controls the AC / DC conversion unit and the DC / DC conversion unit to convert alternating current into direct current, and the voltage The capacity detected by the detection unit And a determination unit that determines whether or not the voltage of the power storage device acquired by the voltage acquisition unit satisfies a required condition, and the control unit determines that the condition is satisfied by the determination unit In this case, the AC / DC conversion unit and the DC / DC conversion unit are controlled to convert direct current of the power storage device into alternating current.

  A computer program according to an embodiment of the present invention includes a computer that has an AC / DC converter that converts AC and DC bidirectionally, and a DC / DC that is connected to the AC / DC converter and converts DC directly. A computer program for controlling a bidirectional power converter that includes a DC converter and a capacitor that smoothes the direct current converted by the DC / DC converter, and converts alternating current into direct current and direct current into alternating current, A voltage acquisition unit that acquires a voltage of a power storage device connected to the DC / DC conversion unit via an electric circuit having an opening / closing unit, and the AC to convert alternating current into direct current when the opening / closing unit is open. A control unit that controls the DC / DC conversion unit and the DC / DC conversion unit, and the capacity when the AC / DC conversion unit and the DC / DC conversion unit are controlled to convert alternating current into direct current. The voltage of the power storage device and the voltage of the power storage device function as a determination unit that determines whether or not a required condition is satisfied, and when the control unit determines that the condition is satisfied, the direct current of the power storage device is changed to an alternating current. The AC / DC converter and the DC / DC converter are controlled to perform conversion.

  A control method for a bidirectional power converter according to an embodiment of the present invention includes an AC / DC converter that converts AC and DC in both directions, and a DC that is connected to the AC / DC converter and converts DC in both directions. A bidirectional power converter control method comprising: a DC / DC converter that performs conversion; and a capacitor that smoothes the direct current converted by the DC / DC converter, and converts alternating current into direct current and direct current into alternating current. The AC / DC conversion unit is configured to acquire a voltage of an electric storage device connected to the DC / DC conversion unit via an electric circuit having a unit, and to convert alternating current into direct current with the open / close unit open. When the control unit controls the DC / DC conversion unit and the AC / DC conversion unit and the DC / DC conversion unit are controlled to convert alternating current into direct current, the voltage detection unit detects the voltage of the capacitor. The detected electric power of the capacitor When the determination unit determines whether or not the acquired voltage of the power storage device satisfies a required condition, and the control unit determines that the condition is satisfied, the direct current of the power storage device is converted into an alternating current. The AC / DC converter and the DC / DC converter are controlled accordingly.

  The bidirectional power converter is connected to an AC / DC converter and an AC / DC converter that convert AC and DC in both directions, and includes a DC / DC converter and a DC / DC converter that convert DC directly. A capacitor for smoothing the converted direct current is provided, and power is converted bidirectionally from alternating current to direct current and from direct current to alternating current. When charging the power storage device, the AC / DC conversion unit converts alternating current into direct current, and the DC / DC conversion unit converts the direct current converted by the AC / DC conversion unit into a voltage and outputs it. When discharging the power storage device, the DC / DC conversion unit converts the direct current of the power storage device into a voltage, and the AC / DC conversion unit converts the direct current converted by the DC / DC conversion unit into an alternating current and outputs it. To do.

  A voltage acquisition part acquires the voltage of the electrical storage device (for example, battery) connected to a DC / DC conversion part via the electric circuit which has an opening / closing part. The voltage of the power storage device can be obtained from a device such as a battery monitoring device that monitors the voltage, current, etc. of the power storage device using a predetermined communication function. Note that the voltage of the power storage device may be directly detected and acquired.

  The control unit controls the AC / DC conversion unit and the DC / DC conversion unit to convert alternating current to direct current when the opening / closing portion is in an open state (a state where the DC / DC conversion portion and the power storage device are not electrically connected). To do. In this case, the AC / DC converter converts AC from the commercial power source into DC, and the DC / DC converter converts the DC converted by the AC / DC converter and outputs the voltage. Although the capacitor is charged, the electricity storage device is not charged because the opening / closing part is in the open state.

  The voltage detection unit detects the voltage of the capacitor when the control unit controls the AC / DC conversion unit and the DC / DC conversion unit to convert alternating current into direct current. Since the capacitor is a capacitor for smoothing the direct current converted by the DC / DC converter, it is provided between the DC / DC converter and the power storage device and between the AC / DC converter and the DC / DC converter. Can do. The voltage detection unit detects the voltage of the capacitor provided between the DC / DC conversion unit and the power storage device, but the voltage of the capacitor provided between the AC / DC conversion unit and the DC / DC conversion unit is detected. It may be detected.

  The determination unit determines whether or not the voltage of the capacitor detected by the voltage detection unit and the voltage of the power storage device acquired by the voltage acquisition unit satisfy a required condition. The required condition means that the voltage of the capacitor and the voltage of the power storage device are equivalent. For example, the voltage of the capacitor and the voltage of the power storage device are equal, or the potential difference between the voltage of the capacitor and the voltage of the power storage device. Can be within a predetermined range.

  The control unit controls the AC / DC conversion unit and the DC / DC conversion unit to convert direct current into alternating current when the determination unit determines that the required condition is satisfied.

  That is, when the bidirectional power converter is discharged (converted from direct current to alternating current), the alternating current is first converted into direct current, and the smoothing capacitor is charged in advance. When the voltage of the capacitor becomes equal to the voltage of the electricity storage device, the electricity storage device is connected to the bidirectional power conversion device to convert direct current into alternating current. When direct current is supplied from the power storage device to the DC / DC converter, the voltage of the capacitor is equal to the voltage of the power storage device, so that no steep current for charging the capacitor is generated. Thereby, even if it does not comprise an inrush current prevention circuit, the excessive inrush current which flows from an electrical storage device to a bidirectional | two-way power converter device can be prevented.

  A bidirectional power conversion device according to an embodiment of the present invention includes a charge rate acquisition unit that acquires a charge rate of the power storage device, and the determination unit is configured to perform the determination based on the charge rate acquired by the charge rate acquisition unit. It is determined whether or not the condition is satisfied.

  The charging rate acquisition unit acquires the charging rate of the power storage device. The state of charge (SOC) of the power storage device can be obtained by using a predetermined communication function from a device such as a battery monitoring device that monitors the charge rate of the power storage device.

  The determination unit determines whether or not a necessary condition is satisfied based on the charging rate acquired by the charging rate acquisition unit. When the charging rate of the power storage device is equal to or higher than a predetermined upper limit value, it is desirable to avoid charging the power storage device. In addition, when the charging rate of the power storage device is less than the predetermined upper limit value, there is no problem even if the power storage device is charged. Therefore, the determination unit determines that the required condition is satisfied when the voltage of the smoothing capacitor is equal to or lower than the voltage of the power storage device. In addition, the determination unit determines that the required condition is satisfied when the voltage of the smoothing capacitor does not become much higher than the voltage of the power storage device. Since it is determined whether or not the required condition is satisfied based on the charging rate of the electricity storage device, even if a precharged capacitor is electrically connected to the electricity storage device, it is prevented from adversely affecting the electricity storage device. Can do.

  In the bidirectional power conversion device according to the embodiment of the present invention, the determination unit is configured to detect the capacitor detected by the voltage detection unit when the charging rate acquired by the charging rate acquisition unit is equal to or greater than a predetermined upper limit value. Is determined to satisfy the condition when the voltage is equal to or higher than the lower limit voltage lower than the voltage of the power storage device and equal to or lower than the voltage of the power storage device.

  The determination unit, when the charging rate acquired by the charging rate acquisition unit is equal to or higher than a predetermined upper limit value, the voltage of the capacitor detected by the voltage detection unit is equal to or higher than the lower limit voltage lower than the voltage of the power storage device, and It is determined that the required condition is satisfied when the voltage is lower than the voltage.

  Since the voltage of the capacitor is equal to or higher than the lower limit voltage lower than the voltage of the power storage device, when the bidirectional power converter is discharged (converted from direct current to alternating current), a steep current for charging the capacitor is not generated. Thereby, even if it does not comprise an inrush current prevention circuit, the excessive inrush current which flows from an electrical storage device to a bidirectional | two-way power converter device can be prevented. In addition, since the voltage of the capacitor is equal to or lower than the voltage of the power storage device, even when a precharged capacitor is electrically connected to the power storage device, it is possible to avoid charging the power storage device and adversely affect the power storage device. Can be prevented.

  In the bidirectional power conversion device according to an embodiment of the present invention, the determination unit detects the capacitor detected by the voltage detection unit when the charging rate acquired by the charging rate acquisition unit is less than a predetermined upper limit value. Is not less than the lower limit voltage lower than the voltage of the electricity storage device and not more than the upper limit voltage higher than the voltage of the electricity storage device, it is determined that the condition is satisfied.

  When the charging rate acquired by the charging rate acquisition unit is less than a predetermined upper limit value, the determination unit has a voltage of the capacitor detected by the voltage detection unit that is equal to or higher than a lower limit voltage lower than the voltage of the storage device, and the voltage of the storage device It is determined that the required condition is satisfied when the voltage is not higher than the upper limit voltage.

  Since the voltage of the capacitor is equal to or higher than the lower limit voltage lower than the voltage of the power storage device, when the bidirectional power converter is discharged (converted from direct current to alternating current), a steep current for charging the capacitor is not generated. Thereby, even if it does not comprise an inrush current prevention circuit, the excessive inrush current which flows from an electrical storage device to a bidirectional | two-way power converter device can be prevented. Further, since the charging rate of the electricity storage device is less than the predetermined upper limit value, there is no problem even if the electricity storage device is charged. And since the voltage of the capacitor is lower than the upper limit voltage higher than the voltage of the electricity storage device, even when the electricity storage device is charged, the peak of the current flowing to the electricity storage device can be suppressed, and the electricity storage device can be adversely affected. Can be prevented.

[Details of the embodiment of the present invention]
Hereinafter, the present invention will be described with reference to the drawings illustrating embodiments. FIG. 1 is an explanatory diagram illustrating an example of a circuit configuration of the bidirectional power converter 1 according to the present embodiment. The bidirectional power conversion device 1 according to the present embodiment is an insulating power conversion device that is mounted on, for example, a plug-in hybrid vehicle or an electric vehicle and bi-directionally converts AC and DC. The bidirectional power conversion device 1 includes AC side terminals T1 and T2 connected to a commercial power source 2, and DC side terminals T3 and T4 connected to a battery 3 as a power storage device. The battery 3 is, for example, a lithium ion battery, but is not limited thereto.

  As shown in FIG. 1, the bidirectional power conversion device 1 has a noise filter 4, a PFC (Power Factor Correction) function, an AC / DC conversion unit 5 that bidirectionally converts AC and DC, and AC / DC conversion. DC / DC conversion unit 6 that is connected to unit 5 to convert direct current bidirectionally, capacitors C2 and C3 that smooth the direct current converted by DC / DC conversion unit 6, and control unit 9 are provided to convert alternating current to direct current. Furthermore, direct current is converted into alternating current.

  The control unit 9 controls on / off of each transistor described later that constitutes the AC / DC conversion unit 5 and the DC / DC conversion unit 6. The control unit 9 includes a voltage detection unit 91, a communication unit 92, a determination unit 93, and the like.

  When charging the battery 3, the AC / DC conversion unit 5 converts alternating current into direct current, and the DC / DC conversion unit 6 converts the direct current converted by the AC / DC conversion unit 5 into a voltage and converts it into a direct current side terminal T3. , Output from T4. When the battery 3 is discharged, the DC / DC converter 6 converts the direct current of the battery 3 into a voltage, and the AC / DC converter 5 converts the direct current converted by the DC / DC converter 6 into an alternating current. And output from the AC side terminals T1 and T2.

  The AC / DC converter 5 has a circuit in which a series circuit in which transistors 51 and 52 are connected in series and a series circuit in which transistors 53 and 54 are connected in series are connected in parallel. As the transistors 51, 52, 53, and 54, for example, an IGBT (Insulated Gate Bipolar Transistor) can be used. However, the present invention is not limited to this, and a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) is used instead of the IGBT. It can also be used. In addition, diodes 55, 56, 57, and 58 are connected in antiparallel between the collectors and emitters of the transistors 51, 52, 53, and 54 (the cathode is connected to the collector and the anode is connected to the emitter).

  One end of the coil L1 is connected to the connection point between the emitter of the transistor 51 and the collector of the transistor 52, and one end of the coil L2 is connected to the connection point between the emitter of the transistor 53 and the collector of the transistor 54. is there. One end of the parallel circuit of the relay S1 and the resistor R is connected to the other end of the coil L1, and the other end of the parallel circuit and the other end of the coil L2 are connected to the AC side T1 via the noise filter 4, respectively. , T2. A capacitor C1 is connected between the other ends of the coils L1 and L2.

  The parallel circuit of the relay S1 and the resistor R prevents a steep current flowing from the commercial power source 2 to the bidirectional power converter 1 when the bidirectional power converter 1 is charged (converted from AC to DC). It is a circuit for. First, by opening the relay S1, the steep pulsed current peak (peak value) and pulse width flowing from the commercial power source 2 are suppressed by the resistor R. The relay S1 is closed when the pulsed current becomes sufficiently small.

  The DC / DC converter 6 includes a series circuit in which a transistor 61 and a transistor 62 are connected in series, and a series circuit in which a transistor 63 and a transistor 64 are connected in series, and the series circuits are connected in parallel. Specifically, the emitter of the transistor 61 and the collector of the transistor 62 are connected, and the emitter of the transistor 63 and the collector of the transistor 64 are connected. The collectors of the transistors 61 and 63 are connected to each other, and the emitters of the transistors 62 and 64 are connected to each other. The emitters of the transistors 62 and 64 are connected to the emitters of the transistors 52 and 54 of the AC / DC converter 5, and the collectors of the transistors 61 and 63 are connected to the collectors of the transistors 51 and 53 of the AC / DC converter 5. It is.

  One side of the transformer 7 is connected to a connection point between the emitter of the transistor 61 and the collector of the transistor 62 and a connection point between the emitter of the transistor 63 and the collector of the transistor 64. Further, diodes 65, 66, 67, and 68 are connected in antiparallel between the collectors and emitters of the transistors 61, 62, 63, and 64, respectively.

  The DC / DC converter 6 includes a series circuit in which the transistor 81 and the transistor 82 are connected in series, and a series circuit in which the transistor 83 and the transistor 84 are connected in series, and the series circuits are connected in parallel. Specifically, the emitter of the transistor 81 and the collector of the transistor 82 are connected, and the emitter of the transistor 83 and the collector of the transistor 84 are connected. The collectors of the transistors 81 and 83 are connected to each other, and the emitters of the transistors 82 and 84 are connected to each other. The emitters of the transistors 82 and 84 are connected to the DC side terminal T4.

  One end of the inductor L3 is connected to the collectors of the transistors 81 and 83, and the other end of the inductor L3 is connected to the DC side terminal T3. A smoothing capacitor C3 for smoothing the direct current converted by the DC / DC converter 6 is connected between the direct current side terminals T3 and T4. The battery 3 is connected via the contactor unit 10 between the DC side terminals T3 and T4.

  The contactor unit 10 has a function as an opening / closing part, and opens and closes a relay S2 that opens and closes an electric path that connects the DC side terminal T3 and the positive side of the battery 3, and opens and closes an electric path that connects the DC side terminal T4 and the negative side of the battery 3. Relay S3 and the like.

  The other side of the transformer 7 is connected to a connection point between the emitter of the transistor 81 and the collector of the transistor 82 and a connection point between the emitter of the transistor 83 and the collector of the transistor 84. Further, diodes 85, 86, 87, 88 are connected in antiparallel between the collectors and emitters of the transistors 81, 82, 83, 84, respectively.

  Between the AC / DC converter 5 and the DC / DC converter 6, a smoothing capacitor for smoothing the direct current converted by the AC / DC converter 5 and the direct current converted by the DC / DC converter 6 C2 is connected. That is, the capacitor C2 is connected between the collector of the transistor 61 and the emitter of the transistor 62.

  The control unit 9 controls the transistors 61, 62, 63, and 64 to be turned on / off at a predetermined frequency (for example, 50 kHz, but not limited thereto). For example, an IGBT (Insulated Gate Bipolar Transistor) can be used as the transistors 61, 62, 63, and 64. However, the present invention is not limited to this, and a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) is used instead of the IGBT. It can also be used.

  In addition, the control unit 9 controls the transistors 81, 82, 83, and 84 to be turned on / off at a predetermined frequency (for example, 50 kHz, but not limited thereto). For example, an IGBT (Insulated Gate Bipolar Transistor) can be used as the transistors 81, 82, 83, and 84, but the present invention is not limited to this, and a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) is used instead of the IGBT. It can also be used.

  The communication part 92 has a function as a voltage acquisition part, and acquires the voltage of the battery 3 connected to the DC / DC conversion part 6 via the electric circuit which has relays S2 and S3. The voltage of the battery 3 can be acquired from a device such as a battery monitoring device (not shown) that monitors the voltage, current, etc. of the battery 3 using a predetermined communication function. Note that the voltage of the battery 3 may be directly detected and acquired.

  The control unit 9 includes the AC / DC conversion unit 5 and the DC / DC conversion unit 5 to convert alternating current into direct current when the relays S2 and S3 are in an open state (the DC / DC conversion unit 6 and the battery 3 are electrically disconnected). The DC converter 6 is controlled. In this case, the AC / DC conversion unit 5 converts the alternating current from the commercial power source 2 into a direct current, and the DC / DC conversion unit 6 converts the direct current converted by the AC / DC conversion unit 5 into a voltage and outputs it. The capacitors C2 and C3 are charged, but the battery 3 is not charged because the relays S2 and S3 are open.

  The voltage detector 91 detects the voltage Vc2 of the capacitor C2 and the voltage Vc3 of the capacitor C3. In the example of FIG. 1, the voltage Vc2 of the capacitor C2 and the voltage Vc3 of the capacitor C3 are both detected, but only one of them may be detected. In the following description, the voltage detection unit 91 detects the voltage Vc3 of the capacitor C3.

  The voltage detection unit 91 is provided between the DC / DC conversion unit 6 and the battery 3 when the control unit 9 controls the AC / DC conversion unit 5 and the DC / DC conversion unit 6 to convert alternating current into direct current. The voltage Vc3 of the capacitor C3 is detected.

  The determination unit 93 determines whether the voltage Vc3 of the capacitor C3 detected by the voltage detection unit 91 and the voltage Vb of the battery 3 acquired by the communication unit 92 satisfy a required condition. The required condition means that the voltage Vc3 of the capacitor C3 and the voltage Vb of the battery 3 are equivalent. For example, the voltage Vc3 of the capacitor C3 and the voltage Vb of the battery 3 are equal, or the voltage Vc3 of the capacitor C3. And the voltage Vb of the battery 3 can be within a predetermined range.

  When the determination unit 93 determines that the required condition is satisfied, the control unit 9 controls the AC / DC conversion unit 5 and the DC / DC conversion unit 6 to convert direct current to alternating current with the relays S2 and S3 closed. To do.

  That is, when the bidirectional power converter 1 is discharged (converted from direct current to alternating current), the alternating current is first converted into direct current, and the smoothing capacitor C3 (including the capacitor C2) is charged in advance. When the voltage Vc3 of the capacitor C3 becomes equal to the voltage Vb of the battery 3, the relays S2 and 3 are closed from the open state, and the battery 3 is connected to the bidirectional power converter 2 to convert direct current into alternating current. When direct current is supplied from the battery 3 to the DC / DC converter 6, the voltage Vc3 of the capacitor C3 is equal to the voltage Vb of the battery 3, so that the steepness for charging the capacitor C3 (and the capacitor C2) is increased. Current does not occur.

  Thus, bidirectional power conversion from the battery 3 is possible without the inrush current prevention circuit configured by connecting a series circuit of a relay and a resistor in parallel with the relay S2 or the relay S3 of the contactor unit 10, for example. An excessive inrush current flowing through the device 1 can be prevented.

  Further, the communication unit 92 has a function as a charging rate acquisition unit, and acquires the charging rate of the battery 3. The state of charge (SOC) of the battery 3 can be acquired from a device such as a battery monitoring device (not shown) that monitors the state of charge of the battery 3 using a predetermined communication function.

  The determination unit 93 determines whether or not a necessary condition is satisfied based on the charging rate acquired by the communication unit 92. For example, when the charging rate of the battery 3 is greater than or equal to a predetermined upper limit value, it is desirable to avoid charging the battery 3. Therefore, the determination unit 93 determines that a necessary condition is satisfied when the voltage Vc3 of the smoothing capacitor C3 is equal to or lower than the voltage Vb of the battery 3.

  Further, when the charging rate of the battery 3 is less than a predetermined upper limit value, there is no problem even if the battery 3 is charged. Therefore, the determination unit 93 determines that the required condition is satisfied when the voltage Vc3 of the smoothing capacitor C3 is not much higher than the voltage Vb of the battery 3.

  Since it is determined whether or not a required condition is satisfied based on the charging rate of the battery 3, it is possible to prevent the battery 3 from being adversely affected even when the capacitor C3 charged in advance is electrically connected to the battery 3. be able to.

  Next, the above-described required conditions (that is, conditions for starting the discharge operation) will be specifically described. FIG. 2 is an explanatory diagram showing an example of conditions for starting the discharge operation of the bidirectional power converter 1 of the present embodiment. As described above, the bidirectional power conversion device 1 according to the present embodiment charges the capacitors C3 and C2 in advance when starting the discharge operation, that is, when starting the operation of converting from direct current to alternating current. The discharge operation is started when the voltage Vc3 of the capacitor C3 satisfies a required condition (condition for starting the discharge operation). Hereinafter, a description will be given with reference to FIG.

  As shown in FIG. 2, the condition for starting the discharge operation is set based on the charging rate (SOC) of the battery 3. For example, the determination unit 93 has a lower limit in which the voltage Vc3 of the capacitor C3 detected by the voltage detection unit 91 is lower than the voltage Vb of the battery 3 when the charging rate of the battery 3 acquired by the communication unit 92 is greater than or equal to a predetermined upper limit value. When the voltage is equal to or higher than the voltage and equal to or lower than the voltage Vb of the battery 3, it is determined that the required condition is satisfied.

  Since the voltage Vc3 of the capacitor C3 is equal to or higher than the lower limit voltage lower than the voltage Vb of the battery 3, the capacitor C3 (including the capacitor C2) is used when the bidirectional power conversion device 1 is discharged (converted from direct current to alternating current). There is no steep current for charging. Thereby, even if it does not comprise an inrush current prevention circuit, the excessive inrush current which flows into the bidirectional | two-way power converter device 1 from the battery 3 can be prevented. Further, since the voltage Vc3 of the capacitor C3 is equal to or lower than the voltage Vb of the battery 3, even when the capacitor C3 charged in advance is electrically connected to the battery 3, charging the battery 3 can be avoided. 3 can be prevented from being adversely affected.

  Further, the determination unit 93 determines that the voltage Vc3 of the capacitor C3 detected by the voltage detection unit 91 is equal to or higher than the lower limit voltage lower than the voltage Vb of the battery 3 when the charging rate acquired by the communication unit 92 is less than a predetermined upper limit value. Yes, it is determined that the required condition is satisfied when the voltage is equal to or lower than the upper limit voltage higher than the voltage Vb of the battery 3.

  Since the voltage Vc3 of the capacitor C3 is equal to or higher than the lower limit voltage lower than the voltage Vb of the battery 3, the capacitor C3 (including the capacitor C2) is used when the bidirectional power conversion device 1 is discharged (converted from direct current to alternating current). There is no steep current for charging. Thereby, even if it does not comprise an inrush current prevention circuit, the excessive inrush current which flows into the bidirectional | two-way power converter device 1 from the battery 3 can be prevented. Further, since the charging rate of the battery 3 is less than the predetermined upper limit value, there is no problem even if the battery 3 is charged. Since the voltage Vc3 of the capacitor C3 is equal to or lower than the upper limit voltage higher than the voltage Vb of the battery 3, even when the battery 3 is charged, the peak of the current flowing to the battery 3 can be suppressed, and the battery 3 is adversely affected. Can be prevented.

  In the example of FIG. 2, if the voltage Vb of the battery 3 is 300 V, for example, the lower limit voltage can be 299 V and the upper limit voltage can be about 301 V. For example, when the impedance (inductance component + resistance component) of the electric circuit between the battery 3 and the bidirectional power converter 1 is 100 mmΩ, the inrush current can be suppressed to about 10A. Thereby, a transistor having a relatively small rated current can be used, and the component cost can be reduced. In addition, a margin for the rated current can be increased, and deterioration of transistor quality can be prevented. The lower limit voltage and the upper limit voltage can be set as appropriate according to the voltage Vb of the battery 3, the impedance of the electric circuit, and the like.

  As described above, according to the bidirectional power conversion device 1 of the present embodiment, it is not necessary to provide an inrush current prevention circuit in the contactor unit 10 illustrated in FIG. For example, it is not necessary to provide a resistor such as a relay for limiting the current in parallel with the relay S2 or the relay S3 and a circuit such as a relay connected in series with the resistor. This makes it possible to add on the bidirectional power conversion device 1 of the present embodiment to the contactor unit 10 without changing the configuration of the existing contactor unit 10.

  FIG. 3 is an explanatory diagram showing an example of a peripheral circuit including the contactor unit 10. The contactor unit 10 is provided between the battery T3 and the terminals T5 and T6 to which the DC side terminals T3 and T4 of the bidirectional power converter 1 of the present embodiment are connected. The contactor unit 10 has relays S2 and S3 that open and close an electric circuit, and a series circuit of a resistor R1 and a relay S4 is connected in parallel with the relay S2. A battery 120 is connected to terminals T5 and T6 via a DC / DC converter 130. The battery 120 is, for example, a lead battery, and the voltage of the battery 120 is, for example, 14V. A capacitor 140 is connected between the terminals T5 and T6 and the DC / DC converter 130.

  When operating the DC / DC converter 130 and charging the battery 120 with the battery 3, a series circuit of the resistor R1 and the relay S4 is provided in order to reduce the inrush current from the battery 3 to the DC / DC converter 130. . That is, when operating the DC / DC converter 130, the inrush current can be limited by the resistor R1 by setting the relay S2 to the open state and the relays S4 and S3 to the closed state. When the input current of the DC / DC converter 130 becomes stable, the relay S4 is opened and the relay S2 is closed.

  According to the bidirectional power conversion device 1 of the present embodiment, there is no need to change the configuration of the inrush current prevention circuit provided in the contactor unit 10 illustrated in FIG. 3, for example, the value of the resistor R1, the rated power, etc. . This makes it possible to add on the bidirectional power conversion device 1 of the present embodiment to the contactor unit 10 without changing the configuration of the existing contactor unit 10.

  FIG. 4 is a flowchart showing an example of a control method of the bidirectional power conversion device 1 of the present embodiment. For convenience, the control unit 9 will be described below as the main subject of processing. The controller 9 determines whether or not there is a discharge instruction (S11). If there is no discharge instruction (NO in S11), the process of step S11 is repeated. The discharge instruction can be acquired by the communication unit 92, for example. When there is a discharge instruction (YES in S11), the control unit 9 performs conversion from AC to DC (S12), acquires the voltage Vb of the battery 3 (S13), and acquires the charging rate of the battery 3 (S14). ).

  The controller 9 detects the voltage Vc3 of the capacitor C3 (S15), and determines whether or not the detected voltage Vc3 of the capacitor C3 satisfies a required condition (S16). The required conditions can be, for example, the conditions illustrated in FIG. When the required condition is not satisfied (NO in S16), the control unit 9 performs the process of step S15.

  When the required conditions are satisfied (YES in S16), the control unit 9 performs conversion from direct current to alternating current (S17), and ends the process.

  In the control method of the bidirectional power conversion device 1 according to the present embodiment, all or part of the control unit 9 is configured by, for example, a CPU (processor), a RAM (memory), and the like, as shown in FIG. By loading a computer program that defines the processing procedure into a RAM (memory) and executing the computer program by a CPU (processor), the control method of the bidirectional power conversion apparatus 1 can be realized on the computer.

  In the above-described embodiment, the configuration is such that the voltage Vc3 of the capacitor C3 is detected and it is determined whether or not a required condition is satisfied. However, the present invention is not limited to this. For example, the relationship between the voltage Vc3 of the capacitor C3 and the voltage Vc2 of the capacitor C2 is obtained in advance, and instead of the voltage Vc3 of the capacitor C3, the voltage Vc2 of the capacitor C2 is detected and converted to the voltage Vc3 of the capacitor C3. May be.

  The embodiments and examples disclosed above should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above embodiments and examples but by the scope of claims, and is intended to include all modifications and variations within the meaning and scope equivalent to the scope of claims. .

3 Battery 5 AC / DC Converter 6 DC / DC Converter 7 Transformer 9 Controller 10 Contactor Unit 51, 52, 53, 54 Transistor 55, 56, 57, 58 Diode 61, 62, 63, 64, 81, 82, 83, 84 Transistor 65, 66, 67, 68, 85, 86, 87, 88 Diode 91 Voltage detection unit 92 Communication unit 93 Determination unit C1, C2, C3 Capacitor L3 Inductor

Claims (6)

AC / DC converter that converts AC and DC in both directions, DC / DC converter that is connected to the AC / DC converter and converts DC in both directions, and DC that is converted by the DC / DC converter A bidirectional power converter for converting alternating current to direct current and direct current to alternating current,
A voltage acquisition unit for acquiring a voltage of an electric storage device connected to the DC / DC conversion unit via an electric circuit having an opening / closing unit;
A control unit that controls the AC / DC conversion unit and the DC / DC conversion unit to convert alternating current into direct current when the opening and closing unit is in an open state;
A voltage detection unit for detecting the voltage of the capacitor when the control unit controls the AC / DC conversion unit and the DC / DC conversion unit to convert alternating current into direct current;
A determination unit that determines whether the voltage of the capacitor detected by the voltage detection unit and the voltage of the power storage device acquired by the voltage acquisition unit satisfy a required condition;
The controller is
A bidirectional power conversion device that controls the AC / DC conversion unit and the DC / DC conversion unit to convert the direct current of the power storage device into alternating current when the determination unit determines that the condition is satisfied. A charge rate acquisition unit for acquiring a charge rate of the electricity storage device;
The determination unit
The bidirectional power converter according to claim 1, wherein it is determined whether or not the condition is satisfied based on a charging rate acquired by the charging rate acquisition unit. The determination unit
When the charge rate acquired by the charge rate acquisition unit is equal to or higher than a predetermined upper limit value, the voltage of the capacitor detected by the voltage detection unit is equal to or higher than a lower limit voltage lower than the voltage of the power storage device, and the power storage device The bidirectional power conversion device according to claim 2, wherein it is determined that the condition is satisfied when the voltage is equal to or lower than a voltage. The determination unit
When the charge rate acquired by the charge rate acquisition unit is less than a predetermined upper limit value, the voltage of the capacitor detected by the voltage detection unit is equal to or higher than a lower limit voltage lower than the voltage of the power storage device, and The bidirectional power converter according to claim 2 or 3, wherein it is determined that the condition is satisfied when the voltage is equal to or lower than an upper limit voltage higher than a voltage. An AC / DC converter that converts AC and DC in both directions to a computer, a DC / DC converter that is connected to the AC / DC converter and converts DC in both directions, and the DC / DC converter A computer program for controlling a bidirectional power converter that includes a capacitor for smoothing the converted direct current and converts alternating current to direct current and direct current to alternating current,
Computer
A voltage acquisition unit for acquiring a voltage of an electric storage device connected to the DC / DC conversion unit via an electric circuit having an opening / closing unit;
A control unit that controls the AC / DC conversion unit and the DC / DC conversion unit to convert alternating current into direct current when the opening and closing unit is in an open state;
A determination unit that determines whether the voltage of the capacitor and the voltage of the power storage device satisfy a predetermined condition when the AC / DC conversion unit and the DC / DC conversion unit are controlled to convert alternating current into direct current. Function as
The controller is
When it determines with satisfy | filling the said conditions, The computer program which controls the said AC / DC conversion part and DC / DC conversion part to convert direct current of the said electrical storage device into alternating current. AC / DC converter that converts AC and DC in both directions, DC / DC converter that is connected to the AC / DC converter and converts DC in both directions, and DC that is converted by the DC / DC converter A bidirectional power converter control method for converting alternating current to direct current and direct current to alternating current.
The voltage acquisition unit acquires the voltage of the power storage device connected to the DC / DC conversion unit via an electric circuit having an opening / closing unit,
The control unit controls the AC / DC conversion unit and the DC / DC conversion unit to convert alternating current into direct current with the open / close unit in an open state,
When the AC / DC conversion unit and the DC / DC conversion unit are controlled to convert alternating current into direct current, the voltage detection unit detects the voltage of the capacitor,
The determination unit determines whether or not the detected voltage of the capacitor and the acquired voltage of the power storage device satisfy a required condition,
The controller is
The control method of the bidirectional | two-way power converter device which controls the said AC / DC converter and DC / DC converter in order to convert the direct current of the said electrical storage device into alternating current, when it determines with satisfy | filling the said conditions.

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