Bidirectional charging and discharging control device in electric vehicles

Abstract

The present invention relates to a bidirectional charging and discharging control device for an electric vehicle, comprising: a charging circuit unit that receives commercial power and charges a battery pack provided in an electric vehicle; a discharging circuit unit that discharges battery power charged in the battery pack and supplies the discharged battery power to an external load; a super capacitor connected to an output terminal of the charging circuit unit and an input terminal of the discharging circuit unit; a first switching circuit provided between the charging circuit unit and the battery pack; a second switching circuit provided between the charging circuit unit and the super capacitor; and a control unit that controls, when commercial power is connected, the first switching circuit to a charging mode in which the charging circuit unit is connected to the battery pack and the battery pack is charged, and controls, when the state of charge of the battery pack is below a predetermined level range in the charging mode, the second switching circuit to connect the super capacitor to the charging circuit unit such that power from the super capacitor and the charging circuit unit can be used together to charge the battery pack. Accordingly, the charging and discharging circuits may be configured in parallel such that charging and discharging can occur simultaneously. In addition, it is possible to quickly respond to rapid load changes during charging and discharging.

Description

Bidirectional charge / discharge control device for electric vehicles

[0001] The present invention relates to a bidirectional charge / discharge control device for an electric vehicle, and more specifically, to a bidirectional charge / discharge control device provided in an electric vehicle.

[0002]

[0003] Recently, various attempts have been made to utilize electric vehicles in the smart grid sector. In particular, the development and industrialization of V2G (Vehicle to Grid) is actively underway. This system utilizes bidirectional chargers to retransmit the electric energy stored in electric vehicle batteries back to the grid, allowing drivers to store electricity during low-cost periods and then sell it back to KEPCO during high-cost periods.

[0004] However, the existing bidirectional charger / discharger, which is the core of the V2G system, is slow to respond to fluctuating external loads, which limits the efficient movement and use of bidirectional power.

[0005] In addition, conventional bidirectional chargers and dischargers have a problem in that they cannot discharge while charging or charge while discharging because the charging circuit and the discharging circuit are configured in series. In particular, in the case of agricultural electric vehicles, the need for power supply to various electric farm equipment that use AC and DC power is being raised. However, when various electric farm equipment that are powered by DC and AC power are used as a power source, most electric farm equipment have inductive load characteristics, so when starting, a peak current of 2 to 5 times the rated current is input, so it is operated at a level of less than half of the battery discharge capacity, which causes a problem in that the operating efficiency of the system is lowered.

[0006]

[0007] In order to solve the problems described above, the present invention aims to provide a bidirectional charge / discharge control device that configures charge / discharge circuits in parallel so that charging and discharging can occur simultaneously. In addition, the present invention aims to provide a bidirectional charge / discharge control device implemented by combining a supercapacitor capable of quickly responding to sudden load changes during charging and discharging with a semiconductor power switch. In addition, the present invention aims to provide a bidirectional charge / discharge control device capable of monitoring the load within the circuit while transferring power in response to an external AC or DC load, and predicting peak power or sudden load change conditions to control the operation of the semiconductor power switch.

[0008]

[0009] The above object can be achieved by a bidirectional charge / discharge control device in an electric vehicle, comprising: a charging circuit unit for receiving commercial power and charging a battery pack provided in the electric vehicle; a discharge circuit unit for discharging battery power charged in the battery pack and supplying the discharged battery power to an external load; a super capacitor connected to an output terminal of the charging circuit unit and an input terminal of the discharge circuit unit; a first switching circuit provided between the charging circuit unit and the battery pack; a second switching circuit provided between the charging circuit unit and the super capacitor; and a control unit for controlling the first switching circuit when commercial power is connected to a charging mode in which the charging circuit unit is connected to the battery pack and the battery pack is charged, and for controlling the second switching circuit when the state of charge of the battery pack is below a predetermined level range in the charging mode to connect the super capacitor to the charging circuit unit so that power from the super capacitor and the charging circuit unit together charges the battery pack.

[0010] And, the bidirectional charge / discharge control device further includes a third switching circuit provided between the discharge circuit unit and the battery pack; and a fourth switching circuit provided between the discharge circuit unit and the super capacitor, wherein the control unit controls the third switching circuit to connect the discharge circuit unit to the battery pack when an external load is connected, thereby controlling the discharge mode so that power from the battery pack is supplied to the external load, and in the discharge mode, when the size of the internal load or the external load exceeds a certain range or the occurrence of peak power due to an inductive load is predicted, controls the fourth switching circuit to connect the super capacitor to the discharge circuit unit so that power from the super capacitor and the discharge circuit unit are supplied together to the external load.

[0011] In addition, the bidirectional charge / discharge control device may further include a charger connection port to which a charger is connected, and the charging circuit unit may include an AC-DC power conversion unit that receives commercial power from the charger connection port and converts it into DC power.

[0012] In addition, the AC-DC power conversion unit may include an AC-DC converter that receives the commercial power and converts it into a DC voltage, and a DC-DC converter that is connected to the AC-DC converter and converts the DC voltage into a charging voltage of the battery pack.

[0013] In addition, the bidirectional charge / discharge control device may further include an AC load connection port to which a first external load using AC power is connected, and a DC load connection port to which a second external load using DC power is connected, and the discharge circuit unit may include a DC-AC power conversion unit that converts DC power from the battery pack into AC power and supplies AC power to the external AC load, and a DC-DC power conversion unit that converts DC power from the battery pack into voltages of a plurality of DC levels and supplies DC power to the external DC load.

[0014] And, the DC-AC power conversion unit may include a DC-DC converter that converts a DC voltage from the battery pack into a DC voltage of a certain level, and a DC-AC converter that converts the DC voltage into an AC voltage, and the DC-DC power conversion unit may include a DC-DC converter that converts a DC voltage from the battery pack into a DC voltage of a certain level, and a power branch tap for supplying the DC voltage into a plurality of DC levels.

[0015] In addition, the bidirectional charge / discharge control device further includes a fifth switching circuit provided between the input terminal of the charging circuit and the AC load connection port, and the control unit can control the fifth switching circuit to connect the input terminal of the charging circuit and the AC load connection port when the external AC load is connected to the AC load connection port in the charging mode, thereby supplying the commercial power input from the charger connection port to the external AC load.

[0016] In addition, the super capacitor may include a first super capacitor connected to an output terminal of the charging circuit unit, and a second super capacitor connected to an input terminal of the discharging circuit unit.

[0017] The above first switching circuit, the second switching circuit, the third switching circuit, the fourth switching circuit and the fifth switching circuit can be achieved by a bidirectional charge / discharge control device characterized in that it includes a semiconductor power switch.

[0018]

[0019] As described above, the bidirectional charge / discharge control device according to the present invention configures the charge / discharge circuits in parallel, enabling simultaneous charging and discharging. Furthermore, it can quickly respond to rapid load fluctuations during charging and discharging. Furthermore, it can monitor the load within the circuit while transferring power in response to an external AC or DC load, and predict peak power or rapid load fluctuations to control the operation of the semiconductor power switch.

[0020]

[0021] Figure 1 is a schematic diagram of a bidirectional charge / discharge control device for an electric vehicle according to one embodiment of the present invention.

[0022] FIG. 2 is a schematic diagram of a bidirectional charge / discharge control device for an electric vehicle according to another embodiment of the present invention.

[0023] FIG. 3 illustrates an example of a bidirectional charge / discharge circuit including a charging circuit section and a discharging circuit section in a bidirectional charge / discharge control device according to one embodiment of the present invention.

[0024]

[0025] Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

[0026] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, detailed descriptions of well-known functions or components that may obscure the gist of the present invention will be omitted in the following description and the accompanying drawings. It should also be noted that, where possible, identical components are indicated with the same reference numerals throughout the drawings.

[0027] The terms and words used in this specification and claims described below should not be interpreted as limited to their conventional or dictionary meanings, but should be interpreted with meanings and concepts that conform to the technical idea of ​​the present invention based on the principle that the inventor can appropriately define the concept of the term to best describe his or her invention. Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical idea of ​​the present invention. Therefore, it should be understood that there may be various equivalents and modified examples that can replace them at the time of filing this application.

[0028] Hereinafter, an example of an electric vehicle being an agricultural electric vehicle will be described. A bidirectional charge / discharge control device (100) for an electric vehicle according to one embodiment of the present invention is provided within the electric vehicle.

[0029] FIG. 1 is a schematic diagram of a bidirectional charge / discharge control device (100) for an electric vehicle according to one embodiment of the present invention. Referring to FIG. 1, the bidirectional charge / discharge control device (100) for an electric vehicle according to the present embodiment includes a charging circuit unit (110), a discharging circuit unit (120), a super capacitor (130), a first switching circuit (Q1), a second switching circuit (Q2), a third switching circuit (Q3), a fourth switching circuit (Q4), and a control unit (140).

[0030] The charging circuit (110) receives commercial power and charges the battery pack (200) installed in the electric vehicle, and can be implemented as an AC-DC power conversion unit for converting AC power into DC power. A first switching circuit (Q1) is arranged between the charging circuit (110) and the battery pack (200), and is controlled by a control unit (140) described below to connect or disconnect the charging path.

[0031] The discharge circuit unit (120) is intended to discharge the battery power charged in the battery pack (200) and supply it to an external load, and includes a power conversion circuit for converting DC power into AC or DC power. A third switching circuit (Q3) is arranged between the charging circuit unit (110) and the battery pack (200), and is controlled by a control unit (140) described below to connect or block the discharge path.

[0032] The bidirectional charge / discharge control device (100) according to the present invention configures the charging circuit unit (110) and the discharging circuit unit (120) in parallel, thereby enabling charging of the internal battery pack (200) and supply of power to an external load using the power of the battery pack (200) to be performed simultaneously.

[0033] The super capacitor (130) is intended to supply a large current for a short period of time to the charging circuit (110) or the discharging circuit (120) where peak power or momentary overload occurs, and is connected to the output terminal of the charging circuit (110) and the input terminal of the discharging circuit (120), respectively. Although not shown in Fig. 1, a separate charging circuit is provided for charging the super capacitor (130).

[0034] A second switching circuit (Q2) is connected between the charging circuit (110) and the super capacitor (130), and is controlled by a control unit (140) to be described later. When the super capacitor (130) is connected to the charging circuit (110) by the second switching circuit (Q2), the power of the super capacitor (130) is supplied as charging power to the battery pack (200) together with the power of the charging circuit (110).

[0035] Meanwhile, a fourth switching circuit (Q4) is connected between the discharge circuit unit (120) and the super capacitor (130), and is controlled by a control unit (140) to be described later. When the super capacitor (130) is connected to the discharge circuit unit (120) by the fourth switching circuit (Q4), the power of the super capacitor (130) is supplied to an external load together with the power of the discharge circuit unit (120).

[0036] The first switching circuit (Q1), the second switching circuit (Q2), the third switching circuit (Q3), and the fourth switching circuit (Q4) may include semiconductor power switches. The semiconductor power switches may include a field effect transistor (FET), a silicon controlled rectifier (SCR), or an insulated gate bipolar transistor (IGBT).

[0037] The control unit (140) is for controlling the charging and discharging of the bidirectional charging and discharging control device (100), and can be implemented by a control circuit including an MCU (Micro Control Unit), a microcontroller, or a processor.

[0038] The control unit (140) monitors the power load applied to the charging circuit unit (110) and the discharging circuit unit (120) through a plurality of current sensors. Furthermore, the control unit (140) includes a deep learning model for predicting the power load using the monitoring data. In this embodiment, the use of LSTM (LongShort-Term Memory)-AE (Autoencoder) as a deep learning model for predicting the power load is described as an example. The control unit (140) predicts the possibility of occurrence of peak power using the deep learning model, and when a peak power of a certain size or greater is expected, controls the connection state (on / off) of the second switching circuit (Q2) and the fourth switching circuit (Q4) connected between the charging circuit unit (110) and the discharging circuit unit (120) and the super capacitor (130) to enable the movement of power in a stable state.

[0039] When a commercial power source is connected, the control unit (140) controls the first switching circuit (Q1) to switch from a disconnected state to a connected state, thereby controlling the charging mode in which the charging circuit unit (110) is connected to the battery pack (200) and the battery pack (200) is charged. In the charging mode, when the charging circuit unit (110) is out of a stable load range, for example, when a short-term rapid charge is required due to over-discharge or the like, or when the charging state of the battery pack (200) is below a certain level range, the control unit (140) controls the second switching circuit (Q2) to switch from a disconnected state to a connected state so that the super capacitor (130) is connected to the output terminal of the charging circuit unit (110), so that the power of the super capacitor (130) charges the battery pack (200) together with the power from the charging circuit unit (110).

[0040] When an external load is connected, the control unit (140) controls the third switching circuit (Q3) to switch from a disconnected state to a connected state, thereby connecting the discharge circuit unit (120) to the battery pack (200) and controlling it in a discharge mode so that power from the battery pack (200) is supplied to the external load. When the size of the internal load or external load exceeds a certain range in the discharge mode or the occurrence of peak power due to an inductive load is predicted, the control unit (140) controls the fourth switching circuit (Q4) to switch from a disconnected state to a connected state so that the super capacitor (130) is connected to the input terminal of the discharge circuit unit (120) and so that power from the super capacitor (130) is supplied to the external load together with power from the discharge circuit unit (120).

[0041] In this way, the bidirectional charging control device according to the present embodiment switches the fourth switching circuit (Q4) from a disconnected state to a connected state in response to various inductive loads and peak powers so that the power of the super capacitor (130) is supplied to the external load, and when the internal load and the external load are stabilized within a normal range, the fourth switching circuit (Q4) of the super capacitor (130) connected to the discharge circuit (120) is switched to a disconnected state so that the power of the super capacitor (130) is no longer discharged to the external load. Meanwhile, the control unit (140) switches the semiconductor switch (not shown) connected to the charging circuit of the super capacitor (130) to a connected state so that the cycle of charging the discharged super capacitor is efficiently controlled according to the artificial intelligence's judgment of the load situation.

[0042] FIG. 2 is a schematic diagram of a bidirectional charge / discharge control device (100) for an electric vehicle according to another embodiment of the present invention.

[0043] Referring to FIG. 2, a bidirectional charge / discharge control device (100) of an electric vehicle according to the present embodiment includes an AC-DC power conversion unit (charging circuit unit (110)), a DC-AC power conversion unit (121), a DC-DC power conversion unit (123), a first super capacitor (131), a second super capacitor (133), a first switching circuit (Q1), a second switching circuit (Q2), a third switching circuit (Q3), a fourth switching circuit (Q4), a fifth switching circuit (Q5), and a control unit (140). The same reference numerals are used for components common to the embodiment described above in FIG. 2, and, if necessary, any overlapping descriptions are replaced with the descriptions of the embodiment described above and are omitted herein.

[0044] The AC-DC power conversion unit includes an AC-DC converter (111) that converts AC voltage input into DC voltage output, and a DC-DC converter (113) that is connected to the AC-DC converter (111) and converts the DC voltage output into a charging voltage level of the battery pack (200).

[0045] The discharge circuit unit (120) includes a DC-AC power conversion unit (121) that converts DC power from the battery pack (200) into AC power and supplies AC power to an external AC load, and a DC-DC power conversion unit (123) that converts DC power from the battery pack (200) into voltages of multiple DC levels and supplies DC power to an external DC load.

[0046] The DC-AC power conversion unit (121) includes a DC-DC converter that converts DC voltage from a battery pack (200) into a DC voltage of a certain level, and a DC-AC converter that converts DC voltage into AC voltage.

[0047] The DC-DC power conversion unit (123) includes a DC-DC converter that converts the DC voltage from the battery pack (200) into a DC voltage of a certain level, and a power branch tap for converting and supplying the DC voltage into a plurality of DC levels (e.g., 5 V, 12 V, 24 V, etc.).

[0048] Meanwhile, the two-way charge / discharge control device (100) further includes a charger connection port (150) to which a charger is connected, an AC load connection port (160) to which a first external load using AC power is connected, and a DC load connection port (170) to which a second external load using DC power is connected. The AC load connection ports (160) and the DC load connection ports (170) may be provided in multiple numbers as needed. Due to the nature of agricultural work, agricultural electric vehicles often require power supply to various electric agricultural implements (e.g., electric scissors, electric water harvesters, electric sprayers, etc.) that use AC and DC power. For this purpose, the present invention includes an AC load connection port (160) and a DC load connection port (170) to which electric agricultural implements can be connected to the electric vehicle.

[0049] The super capacitor (130) includes a first super capacitor (131) connected to the output terminal of the charging circuit unit (110), and a second super capacitor (133) connected to the input terminal of the discharging circuit unit (120).

[0050] When a charger is connected to the charger connection port (150), the control unit (140) switches the first switching circuit (Q1) from a disconnected state to a connected state to charge the battery pack (200) through the charging circuit unit (110). The control unit (140) monitors the charging and discharging states of the charging circuit unit (110) and the discharging circuit unit (120) as well as changes in the load through internal sensors such as a current sensor, and when short-term rapid charging is required due to over-discharging of the battery pack (200), the control unit (140) switches the second switching circuit (Q2) from a disconnected state to a connected state so that the first super capacitor (131) is connected to the output terminal of the DC-DC converter to charge the battery pack (200) together with the DC-DC converter at the same voltage level as the charging voltage of the battery pack (200). The charging circuit unit (110) and the discharging circuit unit (120) have a current sensor to measure and store the load power being charged and discharged.

[0051] When an external load is connected to the AC load connection port (160) or the DC load connection port (170), the control unit (140) switches the third switching circuit (Q3) from a disconnected state to a connected state, thereby controlling the power of the battery pack (200) to be supplied to the external load through the discharge circuit unit (120). The control unit (140) monitors the charging and discharging status of the charging circuit unit (110) and the discharging circuit unit (120), as well as changes in the load, through internal sensors such as a current sensor, and when it is predicted that the required discharge output will exceed the discharge capacity of the battery, the third switching circuit (Q3) is switched from a disconnected state to a connected state so that the second super capacitor (133) is connected to the input terminal of the discharging circuit unit (120) so that the current of the super capacitor (130) is supplied to the input side of the DC-AC power conversion unit (121) and the DC-DC power conversion unit (123).

[0052] Meanwhile, the bidirectional charge / discharge control device (100) according to the present embodiment further includes a fifth switching circuit (Q5) provided between the input terminal of the charging circuit unit (110) and the AC load connection port (160). The fifth switching circuit (Q5) may include a power semiconductor switch such as a FET, SCR, or IGBT.

[0053] When an external AC load is connected to the AC load connector (160) in the charging mode, the control unit (140) switches the fifth switching circuit (Q5) from a disconnected state to a connected state so that the input terminal of the charging circuit unit (110) and the AC load connector (160) are connected, and commercial power input from the charger connector (150) is supplied to the external AC load through the AC load connector (160). Through this, the input AC power is directly connected to the output AC power, thereby increasing the discharge capability and efficiency of the bidirectional charge / discharge control device (100). This can be very useful, especially in the case of agricultural electric vehicles, when connecting an external electric work tool while stopped or charging to perform work, or when using the PTO output.

[0054] FIG. 3 illustrates an example of a bidirectional charge / discharge circuit (100') including a charging circuit unit (110) and a discharging circuit unit (120) in a bidirectional charge / discharge control device (100) according to one embodiment of the present invention. Referring to FIG. 3, the charging circuit unit (110) includes an AC-DC converter (111) and a DC-DC converter (113). The AC-DC converter (111) can be implemented as a bidirectional inverter. The DC-DC converter (113) is implemented as a bidirectional DC-DC converter, and can include an insulated converter (113') and a non-insulated converter (113").

[0055] The DC-AC power conversion unit (121) includes a DC-DC converter (123A) and a DC-AC converter (121'), and the DC-AC converter (121') can be implemented as a bidirectional inverter. The DC-DC power conversion unit (123) includes a DC-DC converter (123A) and a power branch tap, and the DC-DC converter (123A) is a bidirectional DC-DC converter and can include an insulated converter (123A') and a non-isolated converter (123A").

[0056] In the bidirectional charge / discharge circuit of Fig. 3, the first super capacitor (131) is connected to the output terminal of the DC-DC converter (113), and the second super capacitor (133) is connected to the input terminal of the DC-DC converter (123A). It should be noted that the illustrations of the first to fifth switching circuits (Q1) to (Q5) in Fig. 3 are omitted. Load A (LOAD A) and load B (LOAD B) represent external AC loads connected to the AC load connector (160), and load C (LOAD C) represents an external DC load connected to the DC load connector (170).

[0057] In the above-described embodiment, the bidirectional charge / discharge control device (100) is used as an example of charging using commercial power as input, but it is of course also possible to charge using rapid DC power as input. In this case, the charging circuit unit (110) is implemented as a DC-DC power conversion unit (123) for converting the input DC power into a battery charging voltage. In addition, the charging circuit unit (110) is implemented as a circuit capable of bidirectional charge / discharge, so that the power of the battery pack (200) can be discharged and supplied to the charger. Through this, not only G2V but also V2G can be implemented.

[0058] A bidirectional charge / discharge control device (100) according to another embodiment of the present invention may include a V2G power meter module. The V2G power meter module measures and stores the direction and amount of current during the charging and discharging process, and can exchange information on the amount of power used by the electric vehicle for charging and the amount of power transmitted to the grid through discharging through communication with a smart grid network in accordance with international communication standards for V2G communication (e.g., ISO 15118-20, etc.).

[0059] According to one embodiment of the present invention, a two-way charge / discharge control device (100) for an agricultural electric vehicle not only increases the charge / discharge efficiency of an agricultural electric vehicle and expands the convenience of using the electric vehicle, but also utilizes the battery pack (200) of the agricultural electric vehicle as an emergency power supply device (ESS) through the two-way charge / discharge technology, thereby enabling effective response to power outages at farms or agricultural facilities such as greenhouses or livestock sheds caused by natural disasters or power line failures. Since electricity rates change hourly depending on electricity demand, when an electric vehicle is not being operated or is parked for a long time, it is possible to charge the vehicle during times when electricity demand is low and electricity rates are low, and to transmit electricity through the power grid during times when electricity demand is high and electricity rates are high, thereby providing a new source of income for farms and contributing to the stable operation of the power grid. Since the two-way charge / discharge control device (100) for an agricultural electric vehicle according to this embodiment allows for the free use of electric agricultural equipment that uses AC and DC power, it is expected that the utility of agricultural electric vehicles will be increased and the convenience of farming will be greatly improved.

[0060] While several embodiments of the present invention have been described so far, those skilled in the art will appreciate that modifications or substitutions of certain embodiments may be made without departing from the technical spirit of the present invention. Therefore, the scope of protection of the present invention should be deemed to encompass the inventions described in the claims and their equivalents.

Claims

1. In a two-way charge / discharge control device in an electric vehicle, A charging circuit that receives commercial power and charges a battery pack installed in an electric vehicle; A discharge circuit unit that discharges the battery power charged in the above battery pack and supplies it to an external load; A super capacitor connected to the output terminal of the charging circuit unit and the input terminal of the discharging circuit unit; A first switching circuit provided between the charging circuit and the battery pack; A second switching circuit provided between the charging circuit and the super capacitor; and A bidirectional charge / discharge control device characterized by comprising a control unit that controls the first switching circuit to control the charging circuit to be connected to the battery pack and charge the battery pack when a commercial power source is connected, and controls the second switching circuit to connect the super capacitor to the charging circuit when the state of charge of the battery pack is below a certain level range in the charging mode, so that the super capacitor and the power from the charging circuit are connected together to charge the battery pack.

2. In paragraph 1, The above two-way charge / discharge control device is, A third switching circuit provided between the discharge circuit and the battery pack; and Further comprising a fourth switching circuit provided between the discharge circuit and the super capacitor, A bidirectional charge / discharge control device characterized in that the control unit, when an external load is connected, controls the third switching circuit to connect the discharge circuit unit to the battery pack so that power from the battery pack is supplied to the external load in a discharge mode, and when the size of the internal load or the external load exceeds a certain range in the discharge mode or the occurrence of peak power due to an inductive load is predicted, controls the fourth switching circuit to connect the super capacitor to the discharge circuit unit so that power from the super capacitor and the discharge circuit unit is supplied together to the external load.

3. In paragraph 2, The above two-way charging / discharging control device further includes a charger connection port to which a charger is connected, A bidirectional charge / discharge control device characterized in that the charging circuit unit includes an AC-DC power conversion unit that receives commercial power from the charger connection port and converts it into DC power.

4. In paragraph 3, A bidirectional charge / discharge control device characterized in that the AC-DC power conversion unit includes an AC-DC converter that receives the commercial power and converts it into a DC voltage, and a DC-DC converter that is connected to the AC-DC converter and converts the DC voltage into a charging voltage of the battery pack.

5. In paragraph 3 or 4, The above two-way charge / discharge control device further includes an AC load connection port to which a first external load using AC power is connected, and a DC load connection port to which a second external load using DC power is connected. A bidirectional charge / discharge control device characterized in that the discharge circuit unit includes a DC-AC power conversion unit that converts DC power from the battery pack into AC power and supplies AC power to an external AC load, and a DC-DC power conversion unit that converts DC power from the battery pack into voltages of multiple DC levels and supplies DC power to an external DC load.

6. In paragraph 5, The above DC-AC power conversion unit includes a DC-DC converter that converts the DC voltage from the battery pack into a DC voltage of a certain level, and a DC-AC converter that converts the DC voltage into an AC voltage. A bidirectional charge / discharge control device characterized in that the DC-DC power conversion unit includes a DC-DC converter that converts the DC voltage from the battery pack into a DC voltage of a certain level, and a power branch tap for supplying the DC voltage into a plurality of DC levels.

7. In paragraph 5, The above two-way charge / discharge control device further includes a fifth switching circuit provided between the charging circuit input terminal and the AC load connection port, A bidirectional charge / discharge control device characterized in that the control unit controls the fifth switching circuit to connect the input terminal of the charging circuit unit and the AC load connection port when the external AC load is connected to the AC load connection port in the charging mode, thereby supplying the commercial power input from the charger connection port to the external AC load.

8. In paragraph 1, A bidirectional charge / discharge control device characterized in that the super capacitor includes a first super capacitor connected to an output terminal of the charging circuit unit, and a second super capacitor connected to an input terminal of the discharging circuit unit.

9. In paragraph 8, A bidirectional charge / discharge control device, characterized in that the first switching circuit, the second switching circuit, the third switching circuit, and the fourth switching circuit include semiconductor power switches.

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