Charging and discharging apparatus for vehicle and control method thereof

Abstract

The invention discloses a charging and discharging apparatus for a vehicle and a control method thereof. In an embodiment, a charge / discharge device may include a charge / discharge port, a power factor correction circuit, an input filter unit, a surge protection circuit unit, and a controller configured to, in response to an end of charge through first to third AC terminals of the charge / discharge port, adjust a power factor of the power factor correction circuit. A second switch and a third switch of the input filter unit are sequentially turned off.

Description

Technical Field

[0001] The present disclosure relates to a charging and discharging device for a vehicle. Background Art

[0002] Recently, in accordance with the global trend of reducing carbon dioxide emissions, the demand for electric vehicles configured to generate driving force by driving a motor using electric energy stored in an energy storage device such as a battery, instead of typical internal combustion engine vehicles configured to generate driving force through the combustion of fossil fuels, has greatly increased.

[0003] Such an electric vehicle may include an on-board charger (OBC) configured to recharge the battery using system power. Generally speaking, such an on-board charger (OBC) is composed of a power factor correction circuit (PFC) configured to convert an external AC voltage into a DC voltage and a DC / DC converter configured to adjust the converted DC voltage to a voltage required by the battery.

[0004] When the relay on the input circuit side of the charger is disconnected at the same time as the charging of the electric vehicle is completed as described above, an overvoltage may be generated in the charger instantaneously. In this case, a current path to the ground may be formed for surge protection.

[0005] On the other hand, when a current path to the ground is formed, current may leak along the current path to the ground. Therefore, a solution to reduce the current leakage should be proposed.

[0006] The above matters disclosed in this section are only used to enhance the understanding of the overall background of the present disclosure, and should not be considered as an admission or any form of suggestion that these matters constitute known prior art. Summary of the invention

[0007] The present disclosure relates to a charge and discharge device for a vehicle and a control method thereof, the charge and discharge device being configured to reduce the occurrence of leakage current.

[0008] An embodiment of the present disclosure provides a charging and discharging device for a vehicle and a control method thereof, which can reduce the occurrence of current leakage through a current path to the ground by adjusting the disconnection time point of a switch provided on the input circuit side when charging of a vehicle, such as an electric vehicle, is completed.

[0009] Those skilled in the art to which the present disclosure belongs may understand that the technical problems to be solved by the present disclosure are not necessarily limited to the above-mentioned technical problems.

[0010] According to an embodiment of the present disclosure, a charging and discharging device for a vehicle includes a charging / discharging port, which includes a first AC terminal, a second AC terminal, a third AC terminal, and a neutral terminal. The charging / discharging port can be configured to transmit external power to a battery connected to the charging / discharging port, or to transmit the power of the battery to the outside of the charging / discharging port. Embodiments may include: a power factor correction circuit including a plurality of inductors corresponding to a first AC terminal, a second AC terminal, and a third AC terminal, respectively; an input filter unit including a first switch configured to selectively interconnect the first AC terminal with a corresponding inductor among the plurality of inductors, a second switch configured to selectively interconnect the second AC terminal with a corresponding inductor among the plurality of inductors, and a third switch configured to selectively interconnect the third AC terminal with a corresponding inductor among the plurality of inductors; a surge protection circuit unit connected between the first to third AC terminals and ground, and connected to form a current path to ground when a surge is generated at at least one of the first AC terminal, the second AC terminal, and the third AC terminal; and a controller configured to sequentially disconnect the second switch and the third switch when charging through the first to third AC terminals ends.

[0011] The input filter unit may further include an interleaving switch configured to selectively interconnect the first AC terminal and the second AC terminal.

[0012] The controller may close the staggered switch after opening the second switch, and may then open the third switch after closing the staggered switch.

[0013] The controller may open the interleaving switch after opening the third switch.

[0014] The controller may perform opening of the second switch, closing of the interleaving switch, opening of the third switch, and opening of the interleaving switch at predetermined time intervals.

[0015] The predetermined time interval may be set in consideration of one or both of a time taken to close at least one of the second switch, the interleaving switch, and the third switch and a time taken to open at least one of the second switch, the interleaving switch, and the third switch.

[0016] When charging is completed, the controller may turn off the first switch.

[0017] The surge protection circuit unit may include: a plurality of varistors each connected between a corresponding one of the first to third AC terminals and a corresponding one of the inductors; and an arrester configured to transfer current to ground when a voltage equal to or higher than a predetermined value is applied.

[0018] The first switch may be connected in parallel to the pre-charge resistor.

[0019] When performing charging through the first AC terminal, the second AC terminal, and the third AC terminal, the controller may close the first switch, the second switch, and the third switch.

[0020] According to an embodiment of the present disclosure, a control method of a charging and discharging device includes: when charging through a first AC terminal, a second AC terminal, and a third AC terminal is completed, a controller sequentially turns off a second switch and a third switch.

[0021] The sequential opening may include opening the second switch by the controller and then opening the third switch when the first AC terminal and the second AC terminal are selectively interconnected by the interleaving switch.

[0022] Opening the second switch and then opening the third switch by the controller may include: closing the staggered switch by the controller after opening the second switch; and opening the third switch by the controller after closing the staggered switch.

[0023] The method may further include: after turning off the third switch, turning off, by the controller, the interleaving switch.

[0024] The opening of the second switch, the closing of the interleaved switch, the opening of the third switch, and the opening of the interleaved switch may be performed at predetermined time intervals. The predetermined time interval may be set by considering one or both of a time taken to close at least one of the second switch, the interleaved switch, and the third switch and a time taken to open at least one of the second switch, the interleaved switch, and the third switch.

[0025] The method may further include: when charging is completed, turning off the first switch by the controller.

[0026] The method may further include closing, by the controller, the first switch, the second switch, and the third switch when performing charging through the first AC terminal, the second AC terminal, and the third AC terminal.

[0027] According to an embodiment of the present disclosure, when charging of an electric vehicle is finished, the occurrence of current leakage to the ground can be reduced, and the operation of a ground leakage breaker on the external charger side can be alleviated.

[0028] The advantages of the embodiments of the present disclosure are not necessarily limited to the above advantages, and those skilled in the art may obtain other advantages not described herein from the present specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The above and other features and other advantages of the present disclosure may be more clearly understood through the following detailed description taken in conjunction with the accompanying drawings, in which:

[0030] Figure 1is a circuit diagram of a charging and discharging device for a vehicle according to an embodiment of the present disclosure;

[0031] Figure 2 is a diagram for explaining a control process of a charge and discharge device according to an embodiment of the present disclosure; and

[0032] Figure 3 is a flowchart explaining a control method of a charge and discharge device according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0033] For the embodiments of the present disclosure disclosed herein, the specific structural or functional description is merely an example to describe the embodiments of the present disclosure, and the embodiments of the present disclosure may be implemented in various forms and should not be construed as necessarily being limited to the embodiments described in this specification.

[0034] The specific example embodiments should not be interpreted as necessarily limiting the potential embodiments of the present disclosure, but should be understood to extend to all modifications, equivalents, and substitutes included within the technical scope of the present disclosure.

[0035] Unless otherwise defined, the terms used herein including technical or scientific terms may have the same meaning as the meaning generally understood by those skilled in the art to which the present disclosure belongs. The terms used herein may be interpreted not only based on the definition of any dictionary, but also based on the meaning used in the field to which the present disclosure belongs.

[0036] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings, and the same or similar elements may be denoted by the same reference numerals regardless of the reference numerals in the drawings and redundant descriptions of the same or similar elements may be omitted.

[0037] In the description of the following embodiments, the term "predetermined" may be a parameter used in a process or algorithm, the value of which has been predetermined. According to the embodiment, the value of the parameter may be set at the start of the process or algorithm or during the period of executing the process or algorithm.

[0038] The suffixes “module” and “unit” of elements herein may be used for convenience of description and thus may be used interchangeably.

[0039] In the following description of the embodiments of the present disclosure, when the detailed description of the known functions and configurations incorporated herein may obscure the subject matter of the embodiments of the present disclosure, the detailed description may be omitted. In addition, the embodiments of the present disclosure can be more clearly understood according to the accompanying drawings, but should not necessarily be limited by the accompanying drawings, and it can be understood that all variations, equivalents and alternatives that do not depart from the spirit and technical scope of the present disclosure are included in the present disclosure.

[0040] It will be understood that although the terms "first", "second", etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another.

[0041] When an element is "connected" or "linked" to another element, it should be understood that the element may be directly connected or linked to the other element, or other elements may exist between the two elements. Conversely, when an element is "directly connected" or "directly linked" to another element, it should be understood that no other elements exist between the two elements.

[0042] Unless clearly specified otherwise, a singular expression may include a plural meaning.

[0043] In this specification, the terms "include", "comprising", etc. are intended to indicate the presence of a feature, number, step, operation, element, component, or a combination thereof, and do not exclude another feature, number, step, operation, element, component, or any combination thereof or any addition thereof.

[0044] In addition, the term "unit" or "control unit" used in specific terms such as motor control unit (MCU), hybrid control unit (HCU), etc. is merely a term widely used to designate a controller used to control specific functions of a vehicle, and therefore does not refer to a general functional unit.

[0045] The controller may include: a communication device configured to communicate with another controller or a sensor to thereby control the function to be performed; a memory configured to store an operating system, logic commands, input / output information, etc.; and at least one processor configured to perform the judgment, calculation, determination, etc. required to control the function to be performed.

[0046] According to an exemplary embodiment of the present disclosure, a charging and discharging device for a vehicle and a control method thereof propose that when charging of an electric vehicle, especially charging of an electric vehicle using three-phase power, is completed, a plurality of switches arranged at a circuit arranged at the input side, especially the three-phase power, are sequentially disconnected to reduce current leakage caused by surge generation at the end of charging.

[0047] Figure 1 is a circuit diagram of a charging and discharging device for a vehicle according to an embodiment of the present disclosure.

[0048] Reference Figure 1 , the charging and discharging device according to an embodiment of the present disclosure may include a charging / discharging port 100 , a power factor correction circuit 200 , an input filter unit 300 , a surge protection circuit unit 400 , and a controller 500 . Figure 1Constituent elements associated with the embodiments of the present disclosure are mainly shown, but the charge and discharge device may be actually implemented by including a greater or lesser number of constituent elements than the number of constituent elements shown.

[0049] The charging / discharging port 100 may include a first AC terminal L1, a second AC terminal L2, a third AC terminal L3, and a neutral terminal N. The charging / discharging port 100 may receive external power through the first to third AC terminals L1 to L3, and then may transmit the received power to a battery Bat connected to the charging / discharging port 100, or may transmit the power of the battery Bat to the outside of the charging / discharging port 100.

[0050] The power factor correction circuit 200 may include a plurality of inductors Lcm1 corresponding to the first, second, and third AC terminals L1, L2, and L3, respectively, and may additionally include a plurality of resistors Lcm2.

[0051] The input filter unit 300 may include: a first switch Sw1 configured to selectively interconnect the first AC terminal L1 with a corresponding inductor in the inductor Lcm1, i.e., the inductor Lcm11; a second switch Sw2 configured to selectively interconnect the second AC terminal L2 with a corresponding inductor in the inductor Lcm1, i.e., the inductor Lcm12; and a third switch Sw3 configured to selectively interconnect the third AC terminal L3 with a corresponding inductor in the inductor Lcm1, i.e., the inductor Lcm13. The first switch Sw1, the second switch Sw2, and the third switch Sw3 may be implemented as, for example, relays, but are not necessarily limited thereto. For the first to third switches Sw1 to Sw3, any element capable of interconnecting the respective AC terminals L1 to L3 with the respective inductors Lcm1 may be applied.

[0052] The surge protection circuit unit 400 may be connected between the first to third AC terminals L1 to L3 and the ground Gc, and may form a current path to the ground Gc when a surge is generated at one or more of the first to third AC terminals L1 to L3 .

[0053] In more detail, the surge protection circuit unit 400 can be configured by including a plurality of varistors Va1, Va2, and Va3, and a lightning arrester, each of which is connected between a corresponding one of the first to third AC terminals L1 to L3 and a corresponding one of the inductors Lcm11, Lcm12, and Lcm13, and the lightning arrester is configured to transmit current to the ground Gc when a voltage equal to or higher than a preset, predetermined, or selected value is applied.

[0054] Each of the plurality of varistors Va1, Va2, and Va3 may have a variable resistance such that when a voltage applied thereto increases, its resistance decreases, and thus, when a high voltage is generated, current may be induced to flow to the surge protection circuit unit 400 side. When a surge is generated, the arrester Ar may form a current path to the ground Gc, thereby protecting the charging and discharging equipment from the surge.

[0055] The controller 500 may control switching, ie, closing and opening, of the first to third switches Sw1 to Sw3. In particular, when charging through the first to third AC terminals L1 to L3 is completed, the controller 500 may sequentially open the second switch Sw2 and the third switch Sw3.

[0056] In other words, the controller 500 may disconnect at least the second switch Sw2 and the third switch Sw3 to end charging using the three-phase power applied through the first AC terminal L1, the second AC terminal L2, and the third AC terminal L3. The second switch Sw2 and the third switch Sw3 may be disconnected sequentially instead of being disconnected simultaneously.

[0057] When the second switch Sw2 and the third switch Sw3 are disconnected at the same time, a surge may be generated between the first AC terminal L1 and the inductor Lcm11 corresponding thereto according to the magnitude and phase of the AC voltage at the disconnection time. The surge protection circuit unit 400 may operate to perform surge protection. When a surge is generated, the surge protection circuit unit 400 may form a current path between the first AC terminal L1 and the ground Gc. When the current flows along the formed current path, current leakage may occur. However, as in an embodiment of the present disclosure, when the controller 500 sequentially disconnects the second switch Sw2 and the third switch Sw3, the occurrence of leakage current caused by surge generation may be reduced.

[0058] In more detail, the input filter unit 300 may further include an interleaving switch Sw12 configured to selectively interconnect the first AC terminal L1 with the second AC terminal L2. The controller 500 may turn off the third switch Sw3 after turning off the second switch Sw2.

[0059] In particular, the controller 500 may close the interleaving switch Sw12 after opening the second switch Sw2 , and may then open the third switch Sw3 after closing the interleaving switch Sw12 .

[0060] When the interleaving switch Sw12 is closed, voltage may be applied not only to the first branch Leg1 between the first AC terminal L1 and the inductor Lcm11 corresponding to the first AC terminal L1 , but also to the second branch Leg2 between the second AC terminal L2 and the inductor Lcm12 corresponding to the second AC terminal L2 .

[0061] Therefore, when the third switch Sw3 is in the closed state under the condition that the interleaving switch Sw12 is in the closed state, the voltage can be applied even to the third branch Leg3 between the third AC terminal L3 and the inductor Lcm13 corresponding to the third AC terminal L3. Therefore, the voltage can be applied to all the branches of the first to third branches Leg1 to Leg3 of the three phases, respectively.

[0062] On the other hand, the voltage transmitted to the arrester Ar of the surge protection circuit unit 400 may correspond to the average value of the voltages applied to the first to third branches Leg1 to Leg3, respectively. Therefore, when the number of branches to which the voltages are applied increases, the voltage transmitted to the arrester Ar may decrease. In this case, the current leakage to the ground may be reduced according to the operation of the arrester Ar.

[0063] Thereafter, the controller 500 may disconnect the third switch Sw3, and thus may end the charging of the vehicle in a state where the voltage transmitted to the arrester Ar is reduced. When the charging is ended according to the disconnection of the third switch Sw3, since the voltage applied to the second branch Leg2 is no longer used or required, the interleaving switch Sw12 may be disconnected.

[0064] In this case, the controller 500 may perform the opening of the second switch Sw2 , the closing of the interleaving switch Sw12 , the opening of the third switch Sw3 , and the opening of the interleaving switch Sw12 at preset, predetermined, or selected time intervals.

[0065] In more detail, a preset, predetermined or selected time interval may be set considering at least one of the time taken to close at least one of the second switch Sw2, the interleaved switch Sw12 and the third switch Sw3 and the time taken to open at least one of the second switch Sw2, the interleaved switch Sw12 and the third switch Sw3.

[0066] For example, when the second switch Sw2, the interleaved switch Sw12 and the third switch Sw3 are implemented as the same relay, the predetermined time interval can be determined by the longer time of the operation time taken from the time when the coil voltage is applied to the relay associated with the coil voltage to the time when the relay contact is completed, and the release time taken from the time when the application of the coil voltage is cut off to the time when the release of the relay contact is completed.

[0067] On the other hand, when charging is terminated, the controller 500 may not only disconnect the second switch Sw2 and the third switch Sw3, but also disconnect the first switch Sw1. In particular, the pre-charge resistor Rpch may be connected in parallel to the first switch Sw1. Whether the first switch Sw1 is closed or opened, a voltage may be applied to the first branch Leg1. When or only when the first switch Sw1 is opened, the pre-charge function through the pre-charge resistor Rpch may be performed.

[0068] As described above, the charge and discharge device according to the embodiment of the present disclosure can reduce the transmission of overvoltage to the surge protection circuit unit 400 by preventing the occurrence of a situation where voltage is applied only to the first branch Leg1 at the end of charging by controlling the switching of the second switch Sw2, the third switch Sw3 and the interleaving switch Sw12.

[0069] On the other hand, when charging using three-phase power, for example, charging through the first AC terminal L1, the second AC terminal L2, and the third AC terminal L3 is performed, the controller 500 may close the first switch Sw1, the second switch Sw2, and the third switch Sw3 while opening the interleaving switch Sw12 and the neutral switch SwN connected to the neutral terminal N. Control of switching of the second switch Sw2 and the third switch Sw3 at the end of charging may be performed under the above conditions.

[0070] The charging and discharging device according to the embodiment of the present disclosure can perform not only charging using three-phase power but also charging using single-phase power. In this case, single-phase power can be input through the first AC terminal L1.

[0071] When performing charging using single-phase power, the controller 500 may close the first switch Sw1 , the interleaving switch Sw12 , and the neutral switch SwN connected to the neutral terminal N, while opening the second switch Sw2 and the third switch Sw3 .

[0072] Figure 2 2 is a diagram for explaining a control process of a charge and discharge device according to an embodiment of the present disclosure.

[0073] Figure 2 The phase voltages VL1, VL2, and VL3 of each AC terminal during the charging end process according to an embodiment of the present disclosure, the voltage applied to each branch Leg1, Leg2, and Leg3, the voltage VAr applied to the lightning arrester Ar, and the switching states of the second switch Sw2, the third switch Sw3, and the interleaving switch Sw12 are shown. The voltage VAr applied to the lightning arrester Ar can be represented by the average value of the voltages applied to each branch Leg1, Leg2, and Leg3.

[0074] The controller 500 may perform control of charging using three-phase power by closing the first switch Sw1 , the second switch Sw2 , and the third switch Sw3 while opening the interleaving switch Sw12 and the neutral switch SwN until time t1 .

[0075] When a charging end sequence for ending charging using three-phase power is subsequently generated, the controller 500 may end the pulse width modulation (PWM) control of the charger, and then the second switch Sw2 may be preferentially disconnected to end charging. In this case, the controller 500 may disconnect the first switch Sw1 and the second switch Sw2 together, but may postpone disconnecting the third switch Sw3. In this state, according to the disconnection of the first switch Sw1 and the second switch Sw2, voltage may be applied to the first branch Leg1 and the third branch Leg3, respectively, and the second branch Leg2 may be in a state where no voltage is applied.

[0076] At a time t2 after a preset, predetermined or selected time interval from the time t1 when the second switch Sw2 is disconnected, the controller 500 can close the interleaved switch Sw12, so that a voltage can be applied to the second branch Leg2 even in the disconnected state of the second switch Sw2. The voltage input from the first AC terminal L1 can be applied to the second branch Leg2 via the interleaved switch Sw12. In this state, a voltage can be applied to all branches in the first branch Leg1, the second branch Leg2, and the third branch Leg3, and therefore, the voltage transmitted to the lightning arrester Ar can be reduced. When the voltage transmitted to the lightning arrester Ar is reduced, the occurrence of current leakage to the ground through the lightning arrester Ar can be reduced. Therefore, the operation of an external charger such as an earth leakage circuit breaker connected to the charging and discharging device can be alleviated.

[0077] At time t3 after a preset, predetermined or selected time interval from time t2, the third switch Sw3 can be disconnected under the condition that the voltage transmitted to the lightning arrester Ar has been reduced. At time t4 after a preset, predetermined or selected time interval from time t3, since the closed state of the interleaving switch Sw12 is no longer used or required, the interleaving switch Sw12 can be disconnected.

[0078] Throughout the process, the voltage VAr applied to the arrester Ar may be maintained at a maximum value of less than 600 V. For example, when a voltage of 600 V or more is required to transmit current to the ground through the operation of the arrester Ar, the arrester Ar may not operate during the charging end process, and therefore, the occurrence of current leakage to the ground may be prevented.

[0079] The whole process can be expressed as follows.

[0080] [Table 1]

[0081] Sw1 Sw2 Sw3 Sw12 Wlq Three-phase charging closure closure closure disconnect disconnect Generation of the end-of-charge sequence closure closure closure disconnect disconnect PWM Off closure closure closure disconnect disconnect First sequence (t1~t2) disconnect disconnect closure disconnect disconnect Second sequence (t2~t3) disconnect disconnect closure closure disconnect The third sequence (t3~t4) disconnect disconnect disconnect closure disconnect The fourth sequence (t4~) disconnect disconnect disconnect disconnect disconnect

[0082] Figure 3 is a flowchart explaining a control method of a charge and discharge device according to an embodiment of the present disclosure.

[0083] Reference Figure 3 , when a charging end sequence is generated during charging using three-phase power (operation S310), the controller 500 may end the pulse width modulation control of the charging and discharging device (operation S320), and then, the controller 500 may turn off the second switch Sw2 (operation S330).

[0084] Then, when a predetermined or selected time interval elapses, the controller 500 may close the interleaving switch Sw12 before opening the third switch Sw3 (operation S340), and may open the third switch Sw3 after a predetermined or selected time interval has elapsed from the time when the interleaving switch Sw12 was closed (operation S350).

[0085] Then, when a predetermined or selected time interval elapses, the controller 500 may turn off the interleaving switch Sw12 (operation S360 ) so that all switches are in an off state, and thus, the charge end sequence may be completed (operation S370 ).

[0086] According to various embodiments of the present disclosure as described above, when charging of an electric vehicle is finished, the occurrence of current leakage to the ground can be reduced and the operation of a ground leakage breaker on the external charger side can be alleviated.

[0087] Although example embodiments of the present disclosure have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the disclosure as disclosed in the accompanying claims.

Claims

1. A charging and discharging device for a vehicle, comprising: a charge / discharge port including a first AC terminal, a second AC terminal, a third AC terminal, and a neutral terminal, the charge / discharge port transmitting external power to a battery or transmitting power of the battery to the outside of the charge / discharge port; a power factor correction circuit comprising a plurality of inductors corresponding to the first AC terminal, the second AC terminal, and the third AC terminal, respectively; An input filter unit, comprising: a first switch selectively interconnecting the first AC terminal with a corresponding first inductor of the plurality of inductors; a second switch selectively interconnecting the second AC terminal with a corresponding second inductor of the plurality of inductors; and a third switch selectively interconnecting the third AC terminal with a corresponding third inductor of the plurality of inductors; a surge protection circuit unit connected between the first to third AC terminals and ground and connected to form a current path to ground in response to a surge being generated at one or more of the first, second, and third AC terminals; and The controller is configured to, in response to completion of charging from the first AC terminal to the third AC terminal, sequentially turn off the second switch and the third switch.

2. The device according to claim 1, wherein: The input filter unit further includes an interleaving switch selectively interconnecting the first AC terminal with the second AC terminal.

3. The device according to claim 2, wherein: The controller is configured to close the interleaving switch after opening the second switch, and then open the third switch after closing the interleaving switch.

4. The device according to claim 3, wherein: The controller is configured to open the interleaving switch after opening the third switch.

5. The device according to claim 4, wherein: The controller is configured to perform opening of the second switch, closing of the interleaving switch, opening of the third switch, and opening of the interleaving switch at selected time intervals.

6. The device according to claim 5, wherein: The selected time interval depends on one or any combination of a time taken to close one or more of the second switch, the interleaved switch and the third switch and a time taken to open one or more of the second switch, the interleaved switch and the third switch.

7. The device according to claim 1, wherein: The controller is configured to open the first switch when charging is completed.

8. The device according to claim 1, wherein: The surge protection circuit unit comprises: a plurality of varistors, each varistor connected between a corresponding one of the first to third AC terminals and a corresponding one of the plurality of inductors; and The arrester transmits current to ground in response to a voltage equal to or greater than a selected voltage threshold being applied to the arrester.

9. The apparatus according to claim 1, further comprising: A pre-charging resistor is connected in parallel with the first switch.

10. The device according to claim 1, wherein: The controller is configured to close the first switch, the second switch, and the third switch to perform charging through the first AC terminal, the second AC terminal, and the third AC terminal.

11. A control method for a charging and discharging device for a vehicle, comprising: External power is transferred to the battery through the charge / discharge port, through the input filter unit, and through the power factor correction circuit. The charging / discharging port includes a first AC terminal, a second AC terminal, a third AC terminal and a neutral terminal. The power factor correction circuit includes a plurality of inductors corresponding to the first AC terminal, the second AC terminal, and the third AC terminal, respectively, and The input filter unit includes: a first switch selectively interconnecting the first AC terminal with a corresponding first inductor of the plurality of inductors; a second switch selectively interconnecting the second AC terminal with a corresponding second inductor of the plurality of inductors; a third switch selectively interconnecting the third AC terminal with a corresponding third inductor of the plurality of inductors; and an interleaving switch selectively interconnecting the first AC terminal with the second AC terminal; and In response to the end of charging through the first AC terminal, the second AC terminal, and the third AC terminal, the second switch and the third switch are sequentially turned off.

12. The method according to claim 11, wherein: Sequentially opening includes opening the second switch and then opening the third switch in response to the first AC terminal and the second AC terminal being selectively interconnected by the interleaving switch.

13. The method according to claim 12, wherein: Turning off the second switch and then turning off the third switch comprises: After opening the second switch, closing the interleaving switch; and After closing the interleaving switch, opening the third switch.

14. The method according to claim 13, further comprising: After turning off the third switch, turning off the interleaving switch.

15. The method according to claim 14, wherein: The opening of the second switch, the closing of the interleaving switch, the opening of the third switch, and the opening of the interleaving switch are performed at selected time intervals.

16. The method according to claim 15, wherein: The selected time interval is set according to a time taken to close each of the second switch, the interleaved switch, and the third switch or a time taken to open each of the second switch, the interleaved switch, and the third switch.

17. The method according to claim 11, further comprising: In response to charging being completed, the first switch is turned off.

18. The method according to claim 11, further comprising: The first switch, the second switch, and the third switch are closed to perform charging through the first AC terminal, the second AC terminal, and the third AC terminal.

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