KR102562796B1 - Module for inrush current in electric vehicle supply equipment - Google Patents

Abstract

According to one aspect of the present specification, the inrush current reduction module includes a first connection unit configured to electrically connect or disconnect between a power supply unit in an electric vehicle charging device and an on-board charger in an electric vehicle, and an electrical connection between the power supply unit and the first connection unit. A current limiting unit connected to and configured to reduce inrush current generated when three-phase AC power is applied by the power supply unit, and a second connection unit configured to electrically connect or disconnect between the power supply unit and the first connection unit. and a controller for controlling on/off of the first magnetic contactor of the first connection unit and the second magnetic contactor of the second connection unit. At this time, when three-phase AC power is applied by the power supply unit, the controller changes the first magnetic contactor to an on state to electrically conduct the first connection part, and after the first magnetic contactor is changed to an on state, the controller in advance When the determined period has elapsed, the second magnetic contactors may be changed to an on state to electrically conduct the second connection part.

Description

Inrush current reduction module in electric vehicle charging device {MODULE FOR INRUSH CURRENT IN ELECTRIC VEHICLE SUPPLY EQUIPMENT}

The present specification relates to the field of electric vehicle charging, and more particularly, to an electric vehicle charging device or facility for supplying three-phase AC power to an electric vehicle.

Due to recent carbon dioxide emission regulations, investments in eco-friendly green cars are occurring in each country. Electric vehicles are vehicles that represent these green car projects. In order to use such an electric vehicle, an electric vehicle charging device for charging a battery of the electric vehicle is required, and development thereof is being actively conducted.

1 is an exemplary diagram of an electric vehicle (EV) including an electric vehicle supply equipment (EVSE) and an on-board charger that supply conventional three-phase AC power am. As shown in FIG. 1, the electric vehicle charging device 100 includes a power supply unit 110 for supplying three-phase AC power (eg, 380v AC), a circuit breaker 120 for blocking overcurrent, and an electric vehicle charging device. When the 100 and the electric vehicle 200 are connected, the power supply 110 and the on-board charger 210 are electrically selectively connected to the first connector 120 composed of a magnetic contactor. In addition, the electric vehicle 200 converts the three-phase AC power supplied from the electric vehicle charging device 100 into DC power and charges the onboard charger 210 that stores the converted DC power and the onboard charger 210. It includes a battery 220 to be.

The on-board charger 210 of the electric vehicle 200 basically includes a capacitor bank composed of a plurality of capacitors in order to accumulate converted DC power. This capacitor bank tries to instantaneously introduce a fairly large charge capacity in order to charge the initially empty charge, so the electric vehicle 200 starts to be charged by the supply voltage applied by the electric vehicle charging device 100 At the moment, an inrush current much higher than the standard charging current is generated.

Such an inrush current causes safety and maintenance problems in the EV charging process. In particular, in the electric vehicle charging device 200 that supplies three-phase AC power to the electric vehicle 100, unnecessary operation of the circuit breaker and unnecessary tripping of the earth leakage breaker occur in the charging device due to such an inrush current.

Korea Patent Publication No. 10-2014-0074569

Therefore, in the present specification, in order to reduce the inrush current generated at the beginning of charging, the electric vehicle charging technology that limits the current at the beginning of charging and removes the current limit thereafter is applied to the electric vehicle charging device side (not the electric vehicle side (load side)). The purpose is to provide it to the charging device side).

According to one aspect of the present specification, an inrush current reduction module in an electric vehicle charging device that supplies three-phase AC power to an electric vehicle including an on-board charger electrically connects a power supply unit in the electric vehicle charging device and the on-board charger in the electric vehicle. A first connection portion configured to be connected or disconnected, wherein the first connection portion includes a first magnetic contactor for selectively conducting the first connection portion, and between the power supply unit and the first connection portion. A current limiting unit electrically connected to and configured to reduce an inrush current generated when three-phase AC power is applied by the power supply unit, wherein the current limiting unit includes a current limiting resistor for limiting current. and a second connection portion configured to electrically connect or disconnect between the power supply unit and the first connection portion, wherein the second connection portion is connected in parallel with the current limiting resistor and selectively conducts the second connection portion. The second connection part including a second magnetic contactor, and a controller controlling on/off of the first magnetic contactor of the first connection part and the second magnetic contactor of the second connection part may be included. At this time, when three-phase AC power is applied by the power supply unit, the controller changes the first magnetic contactor to an on state, electrically conducts the first connection part, and turns the first magnetic contactor on. When a predetermined period has elapsed after the change, the second magnetic contactors may be changed to an on state to electrically conduct the second connection part.

As an example, a resistance value of the current limiting resistor may be determined based on an allowable current of the first magnetic contactor and a supply voltage of the power supply unit.

As an embodiment, the allowable power of the current limiting resistor is determined based on the maximum value of the inrush current and the resistance value of the current limiting resistor, the maximum value of the inrush current is proportional to the bank capacitance of the onboard charger, and the onboard It can be characterized as being inversely proportional to the system inductance of the charger.

As an example, the predetermined period for changing the second magnetic contactor into an on-state may be shorter than a period during which 90% of charge is charged in the capacitor bank of the on-board charger.

As an embodiment, a power distribution circuit breaker disposed between the power supply unit, the current limiting unit, and the second connection unit and configured to block overcurrent may be further included.

According to the present specification, by limiting the current in the initial stage of charging to reduce the inrush current instantaneously generated in the initial stage of charging, damage to the circuit in the charging device and unnecessary tripping of the earth leakage breaker due to the inrush current can be prevented.

In addition, according to the present specification, by adding the inrush current reduction function to the electric vehicle charging device side (charging device side) rather than the electric vehicle side (load side), the above-described inrush current is not added to an already manufactured electric vehicle. Charging with a current reduction function can be provided.

1 is a schematic configuration diagram of an electric vehicle charging device and an electric vehicle according to the prior art.
2 is a schematic configuration diagram of an electric vehicle charging device and an electric vehicle to which an inrush current reduction module according to an embodiment of the present specification is applied.
3 is a detailed configuration diagram of an inrush current reduction module of an electric vehicle charging device according to an embodiment of the present specification.
4A is an example of a charging wave generated during charging by an electric vehicle charging device to which an inrush current reduction module according to an embodiment of the present specification is not applied, and FIG. 4B is an example of a charging wave according to an embodiment of the present specification. This is an example of a charging wave generated when charging by an electric vehicle charging device to which an inrush current reduction module is applied.

Hereinafter, an embodiment will be described in detail with reference to the accompanying drawings and the contents described in the accompanying drawings, but the scope to be claimed is not limited or limited by the embodiments.

The terminology used in this specification has been selected as a general term that is currently widely used as much as possible while considering functions, but it may vary according to the intention or custom of a person skilled in the art or the emergence of new technology. In addition, in a specific case, there is also a term arbitrarily selected by the applicant, and in this case, the meaning will be described in the explanation part of the corresponding specification. Therefore, it should be clarified that the terms used in this specification should be interpreted based on the actual meaning of the term and the overall content of this specification, rather than simply the name of the term.

2 is a schematic configuration diagram of an electric vehicle charging device and an electric vehicle to which an inrush current reduction module according to an embodiment of the present specification is applied.

In this specification, the electric vehicle charging device 100 refers to a device that supplies three-phase AC power to the electric vehicle 200 to which an inrush current reduction module including a plurality of magnetic contactors is applied, and the electric vehicle 200 is an electric vehicle. It refers to an electric vehicle configured to convert three-phase AC power supplied from the vehicle charging device 100 into DC power, accumulate the converted DC power, and charge the battery 220 using the converted DC power. In addition, in this specification, a magnetic contactor (MC) is connected to each line corresponding to each phase (R, S, T phase) of the power supply unit 110, and connects power using the electromagnetic force of the built-in coil. means a device that selectively switches

Referring to FIG. 2, the electric vehicle charging device 100 includes a power supply unit 110, a distribution circuit breaker 120, a first connection unit 130, a second connection unit 140, a current limiting unit 150, and a controller ( 160) (controller). In this specification, the remaining components of the electric vehicle charging device 100 except for the power supply unit 110, that is, the distribution circuit breaker 120, the first connection unit 130, the second connection unit 140, and the current limiting unit 150 ) and the controller 160 may be abbreviated as an inrush current reduction module. Depending on the embodiment, the inrush current reduction module may be a module including only the first connection unit 130 , the second connection unit 140 , the current limiting unit 150 and the controller 160 . Also, according to embodiments, the inrush current reduction module may further include a current supply device, a surge protector, and an earth leakage breaker.

As described above with reference to FIG. 1, the power supply unit 110 can supply three-phase AC power (eg, AC 220V or AC 380V), and the distribution circuit breaker 120 is a circuit breaker capable of blocking overcurrent, for example , MCCB (Mold Case Current Breaker) or NFB (No Fuse Breaker).

The first connection unit 130 is configured to electrically connect or disconnect, that is, to selectively connect the power supply 110 in the electric vehicle charging device 100 and the on-board charger 210 in the electric vehicle 200. can For example, when the charging device 100 of the electric vehicle 200 and the electric vehicle 200 are connected through a connection means such as a charging cable (or when charging starts), the first connection part 130 is the power supply unit 110 ) and the on-board charger 210 may be electrically connected. For another example, when the electric vehicle 200 charging device 100 and the electric vehicle 200 are disconnected through a connection means such as a charging cable (or when charging is terminated), the first connection unit 130 may electrically disconnect the power supply 110 and the on-board charger 210.

In one embodiment, the first connection part 130 may include a first magnetic contactor that selectively conducts the first connection part 130 . According to the control signal of the controller 160, the first magnetic contactor is changed from an off state to an on state to electrically conduct the first connection part 130, or it is changed from an on state to an off state to the first connection part 130. ) may not be electrically conductive. When the first connection unit 130 is electrically conductive, the three-phase AC power applied by the power supply unit 110 may be provided to the on-board charger 210 of the electric vehicle 200 .

The current limiting unit 150 electrically connects the power supply unit 110 and the first connection unit 130 and is configured to reduce inrush current generated when three-phase AC power is applied by the power supply unit 110. It can be. For example, when the first magnetic contactor of the first connector 130 is changed from an off state to an on state and the second magnetic contactor of the second connector 140 is in an off state, the current limiting unit 150 is a power supply unit. 110 and the first connection portion 130 may be electrically connected.

In one embodiment, the current limiting unit 150 may include a current limiting resistor that limits the current. These current limiting resistors are resistors that are connected to each line corresponding to each phase (R, S, and T phases) of the power supply unit 110 to reduce an inrush current generated in the initial stage of charging. In the illustrated embodiment, the first resistor is a resistor for limiting the current flowing in the R phase, the second resistor is a resistor for limiting the current flowing in the S phase, and the third resistor is a resistor for limiting the current flowing in the T phase. resistance. In this case, each resistor may have the same resistance value. When the power supply unit 110 and the first connection unit 130 are electrically connected by the current limiting unit 150, the three-phase AC power applied by the power supply unit 110 has a certain level of current limiting. It may be provided as an on-board charger 210 of the electric vehicle 200.

The second connection unit 140 may be configured to electrically connect or disconnect the power supply 110 and the first connection unit 130 . For example, when a predetermined period elapses after the first magnetic contactor of the first connection unit 130 is changed from an off state to an on state, the second connection unit 140 connects the power supply unit 110 with the first connection unit 130. ) can be electrically connected. For another example, when charging is finished, the second connection unit 140 may electrically disconnect the power supply unit 110 and the first connection unit 130 .

In one embodiment, the second connection unit 140 may include a second magnetic contactor connected in parallel with the current limiting resistor and selectively conducting the second connection unit 140 . According to the control signal of the controller 160, the first magnetic contactor is changed from an off state to an on state to electrically conduct the first connection part 130, or it is changed from an on state to an off state to the first connection part 130. ) may not be electrically conductive. When the second connection unit 140 is electrically conductive, the three-phase AC power applied by the power supply unit 110 may be provided to the on-board charger 210 of the electric vehicle 200 without current limitation.

The controller 160 may control on/off of the first magnetic contactor of the first connection part 130 and the second magnetic contactor of the second connection part 140 . The controller 160 may control the first magnetic contactor or the second magnetic contactor by transmitting a control signal to the first magnetic contactor or the second magnetic contactor.

In one embodiment, when three-phase AC power is applied by the power supply unit 110, the controller 160 may change the first magnetic contactor to an on state to electrically conduct the first connection unit 130. For example, when a control signal for starting charging is received from the electric vehicle 200, the controller 160 may change the first magnetic contactor to an on state to electrically conduct the first connector 130. At this time, since the second connection unit 140 is not electrically conducting, the current due to the three-phase AC power applied by the power supply unit 110 passes through the current limiting resistors of the current limiting unit 150 to the first connection unit ( 130, and may flow to the on-board charger 210 of the electric vehicle 200 through the first connection part 130. Since the current flowing through such a “first path” is subject to current limiting by the current limiting resistors in the current limiting unit 150, the charging device 100 of the electric vehicle 200 can reduce the inrush current generated in the initial stage of charging. can

In another embodiment, when a predetermined period elapses after the first magnetic contactor is turned on, the controller 160 may change the second magnetic contactor to the on state to electrically conduct the second connection part 140. there is. For example, when about 100 ms has elapsed after the first magnetic contactor is changed to an on state, the controller 160 can change the second magnetic contactor to an on state to electrically conduct the second connection part 140 . The predetermined period for changing the second magnetic contactor into an on state needs to be appropriately determined because it is related to the decrease in inrush current and thermal damage to the current limiting resistor. In one embodiment, the predetermined period of time may be characterized as shorter than the period during which 90 percent of the charge is charged to the capacitor bank of the on-board charger.

At this time, since the second connection unit 140 is in an electrically conductive state, the current due to the three-phase AC power applied by the power supply unit 110 flows to the first connection unit 130 through the second connection unit 140, It may flow to the on-board charger 210 of the electric vehicle 200 through the first connection part 130 . Since the current flowing through this “second path” is not subject to current limitation by the current limiting unit 150, the charging device 100 of the electric vehicle 200 uses the three-phase AC applied by the power supply unit 110 without current limitation. power can be provided.

Through this, the charging device 100 of the electric vehicle 200 can prevent damage caused by the inrush current by limiting the current in the initial stage of charging, and thereafter does not limit the current, so that the power supply by the power supply unit 110 can be prevented. The three-phase AC power may be provided to the on-board charger 210 of the electric vehicle 200 at a sufficiently high level.

Referring to FIG. 2 , an electric vehicle 200 may include an onboard charger 210 and a battery 220 . In one embodiment, the on-board charger 210 is electrically connected to the first connection part 130 of the charging device 100 of the electric vehicle 200, and the three-phase AC power provided from the charging device 100 of the electric vehicle 200. It may include a rectifier circuit that converts DC power into DC power, a capacitor bank that stores the converted DC power, and a power output circuit that supplies the accumulated DC power to the battery 220 . As an embodiment, the rectifier circuit may be composed of bridge diodes that convert AC power to DC power, and the capacitor bank may be composed of a plurality of capacitors. The bank capacitance of the capacitor bank of the on-board charger 210 and the system inductance of the on-board charger 210 may be used to determine the resistance value of the current limiting resistor to be described below.

In order for the charging device 100 of the electric vehicle 200 to appropriately limit the current and reduce the inrush current, the resistance value of the current limiting resistor of the current limiting unit 150 and the allowable power value are appropriately set in consideration of the system parameters of the charging system. have to decide At this time, the resistance value of the current limiting resistor may be determined based on the allowable current of the first magnetic contactor and the supply voltage of the power supply unit 110 . Because current flows along the first path passing through the current limiting unit 150 and the first connection unit 130 in the initial stage of charging, the allowable current of the first magnetic contactor of the first connection unit 130 determines the current limiting value. Because it plays an important role. Considering the allowable current of the first magnetic contactor as the limiting value of inrush current, the value of the current limiting resistor is a value obtained by dividing the supply voltage of the power supply 110 by the allowable current of the first magnetic contactor according to Ohm's law. For example, when the supply voltage of the power supply unit 110 is 380V and the allowable current of the first magnetic contactor is 40A, the resistance value of the current limiting resistor may be 380/40 = 9.5 (ohms). Therefore, when a resistance of 10 (ohm) is selected as the current limiting resistor, the charging device 100 of the electric vehicle 200 can reduce the inrush current to less than the allowable current of the first magnetic contactor at the initial stage of charging.

In addition, the value of the allowable power of the current limiting resistor is the power formula ( ), it can be determined based on the maximum value of the inrush current and the resistance value of the current limiting resistor. At this time, the maximum value of the inrush current may be determined by the equation below.

(One)

where C _B is the bank capacitance in microfarads and LS is the system inductance in microhenries. At this time,

(2)

(3)

Substituting equation (3) into (1),

becomes,

Because of,

at last,

becomes

Considering the above formula and the resistance value of the current limiting resistor, the power consumption is,

becomes

Generally, since the allowable power is about twice the power consumed, about 50 W can be selected as the allowable power of the current limiting resistor.

3 is a detailed configuration diagram of an inrush current reduction module of an electric vehicle charging device according to an embodiment of the present specification. In FIG. 3, the power supply unit supplies AC power in a 3-phase, 4-wire system as an example, but the same or similar description may also be applied to a case where the power supply unit supplies AC power in a 3-phase, 3-wire system.

Referring to FIG. 3, as in FIG. 2, the inrush current reduction module may include a power distribution circuit breaker 120, a first connection unit 130, a second connection unit 140, a current limiting unit 150, and a controller. . Functions and operations of these components have already been described with reference to FIG. 2, so detailed descriptions thereof are omitted. In addition, the inrush current reduction module may further include a voltage supply device 170 such as a switched mode power supply (SMPS), a surge protector 180, and an earth leakage breaker 190 such as an electric leakage circuit breaker (ELCB).

Here, the SMPS is electrically connected to a single phase (e.g., R phase) and a neutral line (N line) of the three-phase AC power applied by the voltage supply unit, and controls a switch that converts AC power into DC power using a switching transistor. It is a type of power supply. The converted DC power may be transmitted to the controller. As such, when the SMPS is used as a power supply device, since a lot of output noise and electromagnetic waves are generated due to high-frequency switching, a noise filter may be further included as shown. In addition, a separate circuit breaker may be further included. In FIG. 3, the SMPS has been described as the voltage supply device 170 as an example, but it is obvious to those skilled in the art that other similar voltage supply devices 170 may be used for the inrush current reduction module without being limited thereto.

Here, the surge protector 180 (SPD) is a protector electrically connected to each phase of the three-phase AC power supply and configured to suppress a surge voltage, for example, a voltage switching type SPD and a voltage suppression type SPD. can be The voltage switching type SPD is composed of gas tube and air gap elements, which are discharge elements, and is in an open state below the discharge initiation voltage, and is in an instantaneous short-circuit conduction state for a voltage exceeding the discharge initiation voltage. It lasts for up to approximately 2 cycles and operates by automatically returning to the open state when the surge is removed. In addition, the voltage suppression type SPD is composed of elements such as MOV (Metal Oxide Varistor) and semiconductor diodes that have nonlinear voltage/current characteristics, and has a very low impedance against a voltage exceeding the operating voltage. Below, it has a very high impedance and operates so that the voltage is suppressed by the correlation between the line impedance and the SPD impedance.

Here, ELCB means a circuit breaker for the purpose of interrupting leakage as well as overload blocking. The earth leakage breaker 190 may be located at the rear end of the first connection part 130 . In FIG. 3, the ELCB has been described as an example of the earth leakage breaker 190, but it is obvious to those skilled in the art that the earth leakage breaker 190 such as a residual current protective device (RCD) may be used for the inrush current reduction module without being limited thereto. .

4A is an example of a charging wave generated during charging by an electric vehicle charging device to which an inrush current reduction module according to an embodiment of the present specification is not applied, and FIG. 4B is an example of a charging wave according to an embodiment of the present specification. This is an example of a charging wave generated when charging by an electric vehicle charging device to which an inrush current reduction module is applied.

The charging wave in FIG. 4A is a wave measured under the evaluation conditions shown in the following table.

System Detail EV RenaultSamsung SM3 ZE GEN2 for AC charging IEC-61851-1 Charging EVSE Korea ULVAC 22 kw 3 phase changer MCCBs and RCDs Schneider electric 40 A, B type HPI magnetic contactor (MC) LSIS 40A MC

In FIGS. 4A and 4B, the yellow wave represents a CP (control pilot) signal, which is a control signal having a DC ± 12V, 1Khz waveform, the blue wave represents the AC current delivered to the electric vehicle 200, and the red wave represents the electric vehicle charging device (100 ) represents the AC voltage supplied from

Referring to the dotted line portion of FIG. 4A, when a CP signal (eg, a signal in the form of dropping the voltage to a certain level) for controlling to start charging is input to the electric vehicle charging device 100, the electric vehicle charging device 100 AC power is supplied to start charging, and at this time, it can be confirmed that an inrush current of about 103A is instantaneously generated. This is an inrush current that exceeds the charging standard current of 40A, and the progressive circuit breaker may be tripped or the circuit may be damaged by this inrush current.

Referring to the dotted line in FIG. 4B, similarly, when a CP signal (eg, a signal in the form of voltage dropping to a certain level) for controlling to start charging is input to the electric vehicle charging device 100, the electric vehicle charging device 100 ) starts charging by supplying AC power, and at this time, it can be confirmed that an inrush current of about 25A or about 23A is instantaneously generated. This is an inrush current that does not exceed the charging reference current of 40A, and it is possible to prevent unnecessary tripping of the progressive circuit breaker or damage to the circuit by such reduced inrush current.

In addition, although preferred embodiments have been shown and described above, this specification is not limited to the specific embodiments described above, and those skilled in the art in the art to which the specification pertains without departing from the subject matter claimed in the claims Of course, various modifications are possible by the person, and these modifications should not be individually understood from the technical spirit or perspective of the present specification.

100: electric vehicle charging device 200: electric vehicle

Claims (5)

An inrush current reduction module installed in an electric vehicle charging device that supplies three-phase AC power to an electric vehicle including an on-board charger,
A first connection unit including a first magnetic contactor located between the on-board charger and the charging device in the electric vehicle to electrically connect or disconnect;
A second connection unit that includes a second magnetic contactor positioned between a circuit breaker for power supply of an electric vehicle charging device and the first connection unit to electrically connect or disconnect;
It is connected in parallel to the R, S, and T phases of the second connection unit, electrically connected to the first connection unit, and current limiting to reduce inrush current generated when three-phase AC power is applied by the power supply unit. a current limiting unit including a resistor; and
A controller for controlling on/off of the first magnetic contactor of the first connection part and the second magnetic contactor of the second connection part,
The controller :
When three-phase AC power is applied by the power supply unit, the first magnetic contactor is changed to an on state to electrically conduct the first connection unit;
When a predetermined period of time elapses after the first magnetic contactor is changed to an on state, the second magnetic contactors are changed to an on state to electrically conduct the second connection part;
The resistance value of the current limiting resistor is,
Determined based on the allowable current of the first magnetic contactor and the supply voltage of the power supply unit,
The allowable power of the current limiting resistor is,
Determined based on the maximum value of the inrush current and the resistance value of the current limiting resistor, wherein the maximum value of the inrush current is proportional to the bank capacitance of the on-board charger and inversely proportional to the system inductance of the on-board charger,
The predetermined period for changing the second magnetic contactor to an on state is shorter than a period in which 90 percent of the charge is charged in the capacitor bank of the on-board charger,
When the electric vehicle charging device receives a control signal for starting charging from the electric vehicle, the controller changes the first magnetic contactor to an on state to electrically conduct the first connection portion, and the second connection portion is not electrically conducted. In this state, the current flowing through the first path at this time is subject to current limiting by the current limiting resistors in the current limiting unit, thereby reducing the inrush current generated at the beginning of charging the electric vehicle,
When the predetermined period set to be shorter than the period in which 90 percent of the charge is charged in the capacitor bank of the on-board charger has elapsed, the controller changes the second magnetic contactor to an on state to electrically conduct the second connection unit, At this time, the current flowing through the second path is not subject to current limiting by the current limiting unit, and the on-board charger of the electric vehicle is provided with a higher level of three-phase AC power supplied by the power supply unit than in the first path. Inrush current reduction module in electric vehicle charging device.
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