KR101811149B1 - Power Conditioning System for Controlling Reactive Power and Energy Storage System Including The Same - Google Patents

Abstract

According to one aspect of the present invention, the present invention relates to a power management apparatus for a reactive power control which is not to generate a reactive power when the power management apparatus does not perform charging and discharging operations, comprising: a power conversion module for converting AC voltage supplied from a system into DC voltage to supply the same to a battery during the charging, and converting the DC voltage output from the battery into the AC voltage during the discharging to supply the same to the system; an output filter for reducing a harmonic frequency of the AC voltage supplied from the system or the AC voltage converted by the power conversion module through a first output capacitor for selectively supplying a reactive power to the system in accordance with an on and off state of a first switching unit; and a controller for controlling the on and off state of the first switching unit in accordance with the charging and discharging performance of the power conversion module.

Description

TECHNICAL FIELD [0001] The present invention relates to a power management apparatus for reactive power control, and an energy storage system including the power management apparatus.

The present invention relates to an energy storage system, and more particularly to a power management apparatus included in an energy storage system.

The energy storage system stores surplus power generated from renewable energy such as surplus power at night, wind power, and solar energy in the battery, and supplies power stored in the battery to the system in case of peak load or system accident. This will stabilize the system power unstably fluctuating by the renewable energy source and achieve maximum load reduction and load leveling.

Figure 1 shows a typical energy storage system configuration. As shown in FIG. 1, the energy storage system 100 includes a battery 110 and a power conditioning system (PCS) 120.

The battery 110 stores surplus energy provided from the system 130 and supplies energy stored in the system when a peak load or a system fault occurs.

The power management apparatus 120 supplies energy stored in the battery 110 to the system 130 by charging the battery 110 with surplus energy of the system 130 or by discharging the battery 110. [ To this end, the power management apparatus 120 includes a transformer 122, a system interconnection breaker 124, an output filter 126, a power conversion unit (PCU) 128, and a battery- .

The transformer 122 reduces the AC voltage of the system 130 to a predetermined value or boosts the AC voltage output from the power conversion module 128 to a predetermined value.

The grid interrupter 124 interrupts the fault current from flowing into the system 130 or from the power conversion module 128 when an accident occurs. In addition, the system interconnecting circuit breaker 124 connects or disconnects the power conversion module 128 to the system 130.

The output filter 126 reduces the harmonics of the alternating voltage that is reduced by the transformer 122 or reduces the harmonics of the alternating voltage output by the power conversion module 128.

The power conversion module 128 converts the AC voltage filtered by the output filter 126 to a DC voltage or converts the DC voltage supplied from the battery management device 110 to an AC voltage.

The battery-connecting breaker 129 connects or disconnects the battery management device 110 to the power management device 120. [

In the case of the power management apparatus 120 as described above, charge / discharge operations are performed not only for 24 hours but also for a required time or situation. However, when the power management apparatus 120 does not perform the charging / discharging operation, the output capacitor C of the output filter 126 operates as a true load so as to generate the phase ineffective power in the system 130, So that the system stability is adversely affected.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems and it is an object of the present invention to provide a power management apparatus for reactive power control that prevents reactive power from being generated when the power management apparatus does not perform charging and discharging operations and an energy storage system including the same This is a technical problem.

It is another object of the present invention to provide a power management apparatus for reactive power control capable of adjusting the amount of reactive power generated when the power management apparatus does not perform a charge / discharge operation and an energy storage system including the power management apparatus. do.

According to an aspect of the present invention, there is provided a power management apparatus for reactive power control, comprising: an alternating-current power supply unit for converting an alternating-current voltage supplied from a charging system into a direct- A power conversion module for converting a DC voltage into an AC voltage and supplying the AC voltage to the system; An output filter for reducing the harmonic of the alternating voltage supplied by the power conversion module or the alternating voltage supplied from the system through a first output capacitor selectively supplying reactive power to the system in accordance with the on / off state of the first switching unit; And a controller for controlling on / off of the first switching unit according to charging / discharging of the power conversion module.

According to an aspect of the present invention, there is provided an energy storage system including: a battery; And a power management device for connecting the battery to the system, wherein the power management device includes: a power conversion module that supplies power supplied from the system at the time of charging to the battery and supplies power of the battery to the system at the time of discharging; ; An output filter for reducing harmonics of the alternating voltage supplied to or output from the power conversion module through a first output capacitor selectively supplying reactive power to the system in accordance with the on / off state of the first switching unit; And a controller for controlling on / off of the first switching unit.

According to the present invention, by using a switching unit that selectively connects the output capacitor of the power management apparatus to the output filter, the output capacitor is not connected to the output filter when the power management apparatus does not perform the charge / discharge operation, There is an effect that power can be prevented from being generated.

Further, according to the present invention, since the reactive power due to the output capacitor is not generated when the charging / discharging operation of the power management apparatus is not performed, the increase of the system voltage can be suppressed and the stability of the system can be increased have.

According to another aspect of the present invention, there is provided a power management apparatus including a plurality of output capacitors connected in parallel with each other, the power management apparatus comprising: There is an effect that the amount of phase-ineffective power to be supplied to the system can be adaptively adjusted by adjusting the number of output capacitors to be connected.

1 is a block diagram schematically illustrating the configuration of a general battery energy storage system.
2 is a block diagram illustrating a configuration of an energy storage system including a power management apparatus according to a first embodiment of the present invention.
3 is a block diagram illustrating the configuration of an energy storage system including a power management device having an output capacitor coupled with Y wiring.
FIG. 4 is a view showing a configuration of the switching unit shown in FIG. 2. FIG.
5 is a block diagram illustrating a configuration of an energy storage system including a power management apparatus according to a second embodiment of the present invention.
6 is a block diagram illustrating a configuration of an energy storage system including a power management apparatus according to a third embodiment of the present invention.
7 is a block diagram showing the configuration of the controller shown in FIG.

The meaning of the terms described herein should be understood as follows.

The word " first, "" second," and the like, used to distinguish one element from another, are to be understood to include plural representations unless the context clearly dictates otherwise. The scope of the right should not be limited by these terms.

It should be understood that the terms "comprises" or "having" does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

It should be understood that the term "at least one" includes all possible combinations from one or more related items. For example, the meaning of "at least one of the first item, the second item and the third item" means not only the first item, the second item or the third item, but also the second item and the second item among the first item, Means any combination of items that can be presented from more than one.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1st Example

2 is a block diagram illustrating a configuration of an energy storage system including a power management apparatus according to a first embodiment of the present invention.

As shown in FIG. 2, the energy storage system 200 including the power management apparatus according to the first embodiment of the present invention generates power using a renewable energy source such as wind power, sunlight, etc., The power generated by the energy source (hereinafter, referred to as an 'energy source') is charged to the battery included in the energy storage system 200, and the power charged in the battery during the peak load or system fault is discharged to the system, As shown in FIG.

This energy storage system 200 includes a battery 210 and a power management device 220 as shown in FIG.

The battery 210 stores surplus power supplied from the system 230 in accordance with the charging operation of the power management apparatus 220 and is stored in accordance with the discharging operation of the power management apparatus 220 when a peak load or a grid fault occurs And supplies energy to the system (230).

In one embodiment, the battery 210 may be included in the energy storage system 200 in the form of a battery rack in which a plurality of battery modules 210, in which a plurality of batteries 210 are connected in series, are arranged in a stacked structure.

The power management device 220 plays a role of connecting the battery 210 and the system 230. More specifically, the power management apparatus 220 charges the surplus energy of the system 230 to the battery 210 through the charging operation or supplies the energy stored in the battery 210 to the system 230 through the discharging operation do.

2, the power management apparatus 220 includes a transformer 240, a grid interrupter 250, an output filter 260, a power conversion unit (PCU) 270, And a controller 290. The circuit breaker 280 is a circuit breaker for a motor vehicle.

The transformer 240 reduces the AC voltage supplied from the system 230 according to a predetermined voltage ratio and boosts the AC voltage output from the power conversion module 270 according to the voltage ratio to provide the AC voltage to the system 230.

The primary side of the transformer 240 is connected to the side of the system 230 and the secondary side of the transformer is connected to the side of the grid interrupter 250.

The grid interconnect circuit breaker 250 couples the power conversion module 270 to the system 230 or disconnects the power conversion module 270 from the system 230. Accordingly, the grid interrupter 250 can prevent a fault current from flowing into the system 230 or flowing into the power conversion module 270 when an accident occurs.

In one embodiment, when the power conversion module 270 is implemented as a three-phase inverter, the grid interconnect breaker 250 may include an a-phase breaker 250a, a b-phase breaker 250b, c-phase breaker 250c.

The output filter 260 reduces the harmonics of the reduced AC voltage through the transformer 240 or reduces harmonics of the AC voltage output from the power conversion module 270. In one embodiment, the output filter 260 may be configured as an LCL type, as shown in FIG. However, this is only an example and other types of configurations (e.g., LC type filters) would be possible.

An output filter 260 is connected in parallel to the first inductor L1 and the second inductor L2, the first inductor L1 and the second inductor L2, It is assumed that the filter is an LCL type filter composed of a capacitor C. According to this embodiment, the output capacitor C is connected to the node between the first inductor L1 and the second inductor L2.

2, when the power conversion module 270 is implemented as a three-phase inverter, the output filter 260 includes a-phase first inductor L1a, a-phase second inductor L2a Phase first inductor L1b, b-phase second inductor L2b, and b-phase output capacitor Cb, c-phase first inductor L1c, and c-phase output capacitor Cb, An upper second inductor L2c, and a c-phase output capacitor Cc. At this time, the a-phase output capacitor Ca, the b-phase output capacitor Cb, and the c-phase output capacitor Cc may be connected by a delta connection as shown in FIG. 2, Lt; / RTI >

Meanwhile, the output filter 260 according to the present invention includes a switching unit 262 for selectively connecting the output capacitor C to the first and second inductors L1 and L2. Specifically, the switching unit 262 selectively connects the a-phase output capacitor Ca, the b-phase output capacitor Cb, and the c-phase output capacitor Cc to the first inductor L1 and the second inductor L2 A-phase switching unit 262a, b-phase switching unit 262b, and c-phase switching unit 262c, which connect the two a-phase switching units.

Since the operations of the a-phase switching unit 262a, the b-phase switching unit 262b, and the c-phase switching unit 262c constituting the switching unit 262 are the same, 262 will be described in detail.

4 is a diagram showing the configuration of a switching unit 262 according to an embodiment of the present invention. As shown in FIG. 4, the switching unit 262 includes an initial charging module 410 and a main switch 420.

The initial charging module 410 serves to prevent an inrush current that may be generated when the output capacitor C is electrically connected to the first and second inductors L1 and L2. The initial charging module 410 prevents the generation of an inrush current by precharging the output capacitor C during a time period before the power management apparatus 220 reaches a steady state.

This initial charge module 410 includes a resistor 412 and an initial charge switch 414, as shown in FIG.

The resistor 412 and the initial charge switch 414 are connected in series with each other and the initial charge switch 414 serves to connect the resistor 412 to the output capacitor C. [ Specifically, the initial charge switch 414 is kept on for a predetermined period of time (a period of time before the power management apparatus 220 reaches the steady state) The output capacitor C is connected to the first and second inductors L1 and L2 to allow the output capacitor C to be initially charged.

Thereafter, when a predetermined time elapses, the initial charge switch 414 is turned off.

The main switch 420 is connected in parallel with the initial charging module 410. The main switch 420 is for connecting the output capacitor C to the first and second inductors L1 and L2 and is connected to the main switch 420 for a predetermined time The output capacitor C is connected to the first and second inductors L1 and L2 by a predetermined amount of time after the predetermined time elapses.

The on-off operation of the initial charge switch 414 and the main switch 420 is controlled by the controller 290. [ Specifically, when it is determined by the controller 290 that the power conversion module 270 should perform the charge / discharge operation, the initial charge switch 414 is first turned on to initially charge the output capacitor C, The main switch 420 is turned on so that the output capacitor C is electrically connected to the first and second inverters L1 and L2 and the initial charge switch 414 is turned off. This allows the output filter 260 to attenuate the harmonic of the alternating voltage while preventing the inrush current from being generated due to the connection of the output capacitor C.

If it is determined by the controller 290 that the charge / discharge operation of the power conversion module 270 is stopped, the main switch 420 is turned off so that the output capacitor C is connected to the first and second inverters L1 and L2 To be electrically isolated from each other. Accordingly, when the charge / discharge operation of the power conversion module 270 is stopped, the output capacitor C does not operate as a true load with respect to the system 230, thereby preventing generation of the true phase reactive power due to the output capacitor C. do.

Referring again to FIG. 2, the power conversion module 270 performs charging operation under the control of the controller 290 to convert an AC voltage into a DC voltage to charge the battery 210, To an AC voltage and outputs it to the system (230).

In one embodiment, the power conversion module 270 may be implemented as a three-phase inverter configured with a plurality of IGBT switches.

When the charging command value is transmitted from the controller 290, the power conversion module 270 charges the battery 210 with the power corresponding to the charging command value. When the discharging command value is transmitted from the controller 290, And discharges it from the battery 210 and supplies it to the system 230.

Meanwhile, the power conversion module 270 stops the charging operation and the discharging operation when the charge / discharge instruction value transmitted from the controller 290 is zero. That is, the power conversion module 270 stops the operation of the IGBT switch included in the power conversion module 270, thereby stopping the charging operation and the discharging operation.

The battery-interrupting circuit breaker 280 serves to connect the battery 210 to the power management device 220.

The controller 290 controls the charging and discharging operations of the power conversion module 270 and the switching operation of the switching unit 260. To this end, the controller 290 includes an operation control unit 292 and a switching unit control unit 294. In one embodiment, the controller 290 may include a comparator 296, as shown in FIG.

The operation control unit 292 controls the charge / discharge operation of the power management module 270 according to the charge / discharge command value received from the host controller (not shown). The operation control unit 292 receives the charging command value from the host controller and transmits the charging command value to the power conversion module 270 so that the power conversion module 270 charges the battery 210 with power corresponding to the charging command value .

The operation control unit 292 receives the discharge command value from the host controller and transmits the discharge command value to the power conversion module 270 so that the power conversion module 270 discharges power corresponding to the discharge command value from the battery 210 .

Meanwhile, the operation control unit 292 controls the power conversion module 270 to stop the operation when the charge / discharge instruction value received from the host controller is zero. For example, the operation control unit 292 may stop the operation of the power conversion module 270 by turning off the IGBT switch included in the power conversion module 270.

The switching unit control unit 294 controls the switching unit 262 when the power conversion module 270 does not perform the charging and discharging operations, that is, when the charging and discharging operation of the power conversion module 270 is stopped by the operation control unit 292 Off the output capacitor C from the first and second inductors L1 and L2. That is, the switching unit control unit 294 turns off the main switch 420 included in the switching unit 262 when the power conversion module 270 does not perform the charging / discharging operation, 2 inductors L1 and L2. Through this switching operation, it is possible to prevent the output capacitor C from operating as a true load when the power conversion module 270 is not operating, thereby preventing the true reactive power from being supplied to the system 230 .

Meanwhile, when the power conversion module 270 is to perform the charging / discharging operation, that is, when the power conversion module 270 performs the charging operation or the discharging operation by the operation control unit 292 The switching unit 262 is turned on to connect the output capacitor C to the first and second inductors L1 and L2.

Specifically, when it is determined by the operation control unit 292 that the power conversion module 270 performs the charging operation or performs the discharging operation, the switching unit control unit 294 firstly controls the initial charging switch 414 of the switching unit 262 ) For a predetermined period of time to initial charge the output capacitor (C). When a predetermined time has elapsed, the switching unit controller 294 turns on the main switch 420 and turns off the initial charge switch 414 so that the output capacitor C is connected to the first and second inductors L1 and L2 To be connected. Through this switching operation, the inrush current due to the connection of the output capacitor C can be prevented, and the output filter 260 can attenuate the harmonic of the alternating voltage.

On the other hand, in the embodiment described above, when the operation control unit 292 stops the charging or discharging operation of the power conversion module 270, the switching unit control unit 294 turns off the switching unit 262. [ However, in a modified embodiment, in order to protect the system, when the operation control unit 292 stops charging or discharging operation of the power conversion module 270, the switching unit control unit 294 controls the output current of the power conversion module 270 The switching unit 262 can be turned off when the output current is equal to or lower than a predetermined output current setting value.

To this end, the controller 290 according to the present invention may further include a comparison unit 296 as shown in FIG.

The comparison unit 296 compares the output current of the power conversion module 270 with a predetermined output current setting value when the charging or discharging operation of the power conversion module 270 is stopped by the operation control unit 292, Unit control unit 294. [

According to this embodiment, the switching unit control unit 294 stops the charging or discharging operation of the power conversion module 270 by the operation control unit 292, and the output current from the comparison unit 296 is set to a predetermined output current setting value The switching unit 262 is turned off.

On the other hand, even if the charging or discharging operation of the power conversion module 270 is stopped by the operation control unit 292, the switching unit control unit 294 outputs a comparison result that the output current from the comparison unit 296 exceeds a predetermined output current setting value The switching unit 262 is not turned off and the comparison unit 296 waits until the comparison result that the output current is equal to or less than the predetermined output current setting value is received.

Second Example

In the above-described first embodiment, the output filter 260 includes only one output capacitor C for each phase. However, in the second embodiment, as shown in FIG. 5, the output filter 260 may include a plurality of output capacitors C1 to Cn for each phase.

At this time, the plurality of output capacitors C1 to Cn may be connected in parallel with each other. As described above, in the second embodiment, the output filter 260 is composed of a plurality of output capacitors C1 to Cn connected in parallel to each other, so that the phase reactive power can be finely controlled.

According to the second embodiment, the switching unit 262 is commonly connected to the output capacitors C1 to Cn of the respective phases connected in parallel with each other, thereby connecting the output capacitors C1 to Cn of each phase to the first and second output capacitors C1 to Cn, Are commonly connected to the two inductors L1 and L2 or are commonly disconnected from the first and second inductors L1 and L2.

That is, the a-phase switching unit 262a may commonly connect a plurality of a-phase output capacitors C1a to Cna to the a-phase first and the a-phase second inductors L1a and L2a, And are commonly disconnected from the second inductors L1a and L2a.

The b-phase switching unit 262b connects the plurality of b-phase output capacitors C1b to Cnb commonly to the b-phase first and b-phase second inductors L1b and L2b, or the b-phase first and b- And are commonly disconnected from the second inductors L1b and L2b.

The c-phase switching unit 262c commonly connects the plurality of c-phase output capacitors C1c to Cnc to the c-phase first and c-phase second inductors L1c and L2c, or the c-phase first and c- And are commonly disconnected from the second inductors L1c and L2c.

Third Example

In the second embodiment described above, the output filter 260 includes a plurality of output capacitors C1 to Cn connected in parallel to each phase, and the switching unit 262 includes a plurality of output capacitors (C1 to Cn).

However, in the third embodiment, as shown in FIG. 6, the output filter 260 includes the switching units 262_1 to 262_n provided for the plurality of output capacitors C1 to Cn connected in parallel to each other The connections of the output capacitors C1 to Cn can be individually controlled.

That is, the first switching unit 262_1 is electrically connected to the first output capacitor C1 to connect the first output capacitor C1 to the first and second inductors L1 and L2, 2 inductors L1 and L2.

The nth switching unit 262_n may be electrically connected to the n-th output capacitor Cn to connect the n-th output capacitor Cn to the first and second inductors L1 and L2, (L1, L2).

At this time, each of the switching units 262_1 to 262_n is composed of a-phase switching units 262a_1 to 262a_n, b-phase switching units 262b_1 to 262b_n, and c-phase switching units 262c_1 to 262c_n.

According to this embodiment, the controller 290 individually controls the operation of each of the switching units 262_1 to 262n. Hereinafter, the configuration of the controller 290 according to the third embodiment of the present invention will be described in more detail with reference to FIG.

7 is a block diagram schematically showing a configuration of a controller included in the power management apparatus according to the third embodiment of the present invention.

7, the controller 290 of the power management apparatus 220 according to the third embodiment includes an operation control unit 710, a determination unit 720, a determination unit 730, and a switching unit control unit 740 ). The controller 290 may further include a comparison unit 750.

The operation control unit 710 controls the charge / discharge operation of the power management module 270 according to the charge / discharge command value received from the host controller (not shown). The operation control unit 710 receives the charging command value from the host controller and transmits the charging command value to the power conversion module 270 so that the power conversion module 270 charges the battery 210 with the power corresponding to the charging command value .

The operation control unit 710 receives the discharge command value from the host controller and transmits the discharge command value to the power conversion module 270 so that the power conversion module 270 discharges power corresponding to the discharge command value from the battery 210 .

Meanwhile, the operation control unit 710 controls the power conversion module 270 to stop the operation when the charge / discharge instruction value received from the host controller is '0'. For example, the operation control unit 292 may stop the operation of the power conversion module 270 by turning off the IGBT switch included in the power conversion module 270.

When the operation of the power conversion module 270 is stopped by the operation control unit 710, the determination unit 720 receives the amount of reactive power requested from the system 230 from the host controller, 230 and supplies the determination result to the determination unit 730 and the switching unit control unit 740. [

Specifically, when it is determined that the power conversion module 270 can supply the amount of reactive power requested by the system 230, the determination unit 720 transmits the result to the determination unit 730 and the switching unit control unit 740 And if the power conversion module 270 determines that the amount of reactive power requested by the system 230 can not be supplied, the switching unit control unit 740 transmits the result to the switching unit control unit 740.

At this time, the determination unit 720 can calculate the amount of reactive power generated due to the capacitor capacity of each phase connected by the delta connection or the wired connection, and calculate the maximum amount of reactive power that can be supplied based on the number of capacitors in each phase connected in parallel. Accordingly, if the amount of reactive power required in the system is smaller than the maximum amount of reactive power that can be supplied based on the number of parallel-connected capacitors, the determination unit 720 can supply the amount of reactive power required by the system 230 And determines that the amount of reactive power required by the system 230 can not be supplied if the amount of reactive power required in the system is greater than the maximum amount of reactive power that can be supplied based on the number of parallel-connected capacitors in each phase.

The determination of whether or not the determination unit 720 can supply the amount of the reactive power required by the system 230 determines whether the reactive power should be supplied to the maximum (i.e., all of the capacitors should be kept in a connected state) or It is necessary to determine whether the required amount of reactive power should be supplied (that is, only the number of capacitors corresponding to the required amount of reactive power should be connected).

The determination unit 730 determines that the reactive power required by the system 230 can be supplied by the determination unit 720 to the system 230. In this case, The number of output capacitors C1 to Cn to be connected to the capacitor 260 is determined.

In one embodiment, the determination unit 730 determines the output to be connected to the output filter 260 to supply a corresponding amount of reactive power to the system 230 using Equations 1 and 2 below: < EMI ID = The number of capacitors C1 to Cn can be determined.

는 무효전력 양에 대한 지령치를 나타내고,

는 전체 커패시터 연결시 발생하는 무효전력의 양을 나타내며,

은 N번째 커패시터에서 발생하는 무효전력의 양을 나타내고,

는 전체 출력커패시터 개수를 나타내며,

은 출력필터(260)에 연결된 출력커패시터의 개수를 나타낸다. 이때,

은 0 이상이고

이하의 값을 갖는다.In equations (1) and (2)

Represents an instruction value for the amount of reactive power,

Represents the amount of reactive power generated when all the capacitors are connected,

Represents the amount of reactive power generated in the Nth capacitor,

Represents the total number of output capacitors,

Represents the number of output capacitors coupled to the output filter 260. At this time,

Is greater than or equal to zero

Or less.

The determination unit 730 transfers the number of output capacitors C1 to Cn to the switching unit control unit 740, which should be connected to the output filter 260 for reactive power supply.

When the power conversion module 270 is to perform a charging / discharging operation, that is, when the power conversion module 270 performs a charging operation or a discharging operation by the operation control unit 710, the switching unit control unit 740 , And turns on the switching units 262_1 to 262_n to connect the output capacitors C1 to Cn to the first and second inductors L1 and L2.

Specifically, when it is determined by the operation control unit 710 that the power conversion module 270 performs the charging operation or the discharging operation, the switching unit control unit 740 firstly sets the initial charging switch of the switching units 262_1 to 262_n, (414) for a predetermined time to initial charge the output capacitors (C1 to Cn). When a predetermined time has elapsed, the switching unit control unit 740 turns off the initial charge switch 414 and turns on the main switch 420 so that the output capacitors C1 to Cn are turned on by the first and second inductors L1 and L2 . Through this switching operation, the inrush current due to the connection of the output capacitors C1 to Cn can be prevented, and the output filter 260 can attenuate the harmonic of the alternating voltage.

Meanwhile, when the power conversion module 270 does not perform the charging / discharging operation, that is, the charging / discharging operation of the power conversion module 270 is stopped by the operation control unit 710, It is determined that only the number of switching units 262_1 to 262_n equal to the number of output capacitors C1 to Cn determined by the determination unit 730 can be supplied to the system 230 And turns off the remaining switching units 262_1 to 262n. This allows the system 230 to isolate the output capacitors C1-Cn that are not needed for reactive power supply from the output filter 260. [ Through this switching operation, when the power conversion module 270 is not in operation, it is possible to prevent the output capacitors C1 to Cn, which are not needed for supplying the reactive power to the system 230, from operating as a true phase load, It is possible to adjust the amount of reactive power to be supplied to the battery 230.

In one embodiment, the switching unit control unit 740 turns off the switching units 262_1 to 262_n so that the switching unit control unit 740 controls the output current of the power conversion module 270 to protect the system from a predetermined output current The switching units 262_1 to 262_n can be turned off only when the difference is less than the set value. To this end, the controller 290 according to the present invention may further include a comparison unit 750 as shown in FIG.

The comparison unit 750 compares the output current of the power conversion module 270 with a predetermined output current setting value when the charging or discharging operation of the power conversion module 270 is stopped by the operation control unit 710, Unit control unit 740, as shown in FIG.

According to this embodiment, the switching unit control unit 740 stops the charging or discharging operation of the power conversion module 270 by the operation control unit 710, and the output current from the comparison unit 750 is set to a predetermined output current setting value The switching units 262_1 to 262_n of the number determined by the determination unit 730 are turned off.

Therefore, even if the charging or discharging operation of the power conversion module 270 is stopped by the operation control unit 710, the switching unit control unit 740 outputs a comparison result that the output current from the comparison unit 750 exceeds a predetermined output current setting value The switching unit 262_1 to 262_n is not turned off and the comparison unit 750 waits until the comparison result that the output current is equal to or smaller than the predetermined output current setting value is received.

If it is determined by the determination unit 720 that the amount of reactive power requested by the system 230 can not be supplied even though the power conversion module 270 does not perform the charging / discharging operation, the switching unit control unit 740 performs all switching The units 262_1 to 262_n are turned on so that the output capacitors C1 to Cn are connected to the output filter 260. [ This switching operation enables the maximum amount of reactive power that can be provided to the power conversion module 270 to be supplied to the system 230 when the power conversion module 270 is not operating.

It will be understood by those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof.

It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

200: Energy storage system 210: Battery
220: power management device 230: system
240: Transformer 250: Circuit breaker
260: output filter 262: switching unit
270: power conversion module 280: battery connection breaker
290:

Claims (18)

A power conversion module for converting an AC voltage supplied from the system at the time of charging to a DC voltage and supplying the DC voltage to the battery, converting the DC voltage outputted from the battery to AC voltage at the time of discharging,
An output filter for reducing the harmonic of the alternating voltage supplied by the power conversion module or the alternating voltage supplied from the system through a first output capacitor selectively supplying reactive power to the system in accordance with the on / off state of the first switching unit; And
And a controller for controlling on / off of the first switching unit according to charging / discharging of the power conversion module,
The controller comprising:
And a switching unit controller for turning off the first switching unit and disconnecting the first output capacitor from the output filter when the power conversion module does not perform the charging / discharging operation. . delete The method according to claim 1,
The controller comprising:
Further comprising a comparator for comparing an output current of the power conversion module with a preset output current setting value,
Wherein the switching unit control unit turns off the first switching unit when the output current is equal to or lower than the output current setting value as a result of the comparison by the comparison unit when the power conversion module is not performing the charging / discharging operation Power management device for power control. The method according to claim 1,
Wherein the switching unit controller turns on the first switching unit to connect the first output capacitor to the output filter when the power conversion module is performing a charging / discharging operation. The method according to claim 1,
The first switching unit includes:
An initial charge module in which a resistor and a first switch are connected in series; And
And a second switch connected in parallel with the initial charging module. 6. The method of claim 5,
Wherein the switching unit controller turns on the first switch when the power conversion module is performing a charging and discharging operation and turns on the second switch when a predetermined time elapses after the first switch is turned on, And turns off the power supply for the reactive power control. The method according to claim 1,
The controller comprising:
And an operation control unit for turning off the plurality of switches included in the power conversion module to stop charging / discharging operation of the power conversion module when the charge / discharge instruction value for the power conversion module is 0, Power management device for power control. The method according to claim 1,
Wherein the output filter comprises:
Further comprising at least one second output capacitor connected in parallel to the first output capacitor,
Wherein the first switching unit selectively connects the first output capacitor and the one or more second output capacitors to the output filter through a switching operation. The method according to claim 1,
Wherein the output filter comprises:
One or more second output capacitors connected in parallel to the first output capacitor; And
Further comprising at least one second switching unit for selectively coupling the one or more second output capacitors to the output filter,
The controller comprising:
And a determination unit that determines the number of output capacitors to be connected to the output filter among the first and second output capacitors when the power conversion module is not performing a charge / discharge operation,
The switching unit control unit,
And turns on switching units equal in number to the determined number of output capacitors among the first and second switching units. 10. The method of claim 9,
Wherein the determination unit determines the number of output capacitors to be connected to the output filter among the first and second output capacitors according to an amount of reactive power required in the system. . 10. The method of claim 9,
The controller comprising:
Further comprising a determination unit for determining whether or not the supply of the reactive power amount required by the system is available,
Wherein the determining unit determines the number of output capacitors required to supply the amount of reactive power required by the system when it is determined that the amount of reactive power required by the system can be supplied as a result of the determination by the determination unit Power management device for reactive power control. 10. The method of claim 9,
The controller comprising:
Further comprising a determination unit for determining whether or not the supply of the reactive power amount required by the system is available,
The switching unit control unit,
Wherein the control unit turns on both the first and second switching units to connect all the output capacitors to the output filter when it is determined that the reactive power amount requested by the system can not be supplied as a result of the determination, Gt; The method according to claim 1,
The first output capacitor
A-phase capacitor, a b-phase capacitor, and a c-phase capacitor, which are Y-connected or delta-connected,
The first switching unit includes:
An a-phase first switching unit for connecting the a-phase output capacitor, the b-phase output capacitor Cb and the c-phase output capacitor Cc to the output filter, a b-phase first switching unit, and a c- And a switching unit. The method according to claim 1,
Wherein the output filter comprises:
A first inductor;
A second inductor connected in series to the first inductor,
The first output capacitor electrically coupled to a node between the first inductor and the second inductor; And
And the first switching unit selectively connecting the first output capacitor to a node between the first inductor and the second inductor through a switching operation. battery;
And a power management device for associating the battery with the system,
The power management apparatus includes:
A power conversion module that supplies power supplied from the system at the time of charging to the battery and supplies power of the battery to the system at the time of discharging;
An output filter for reducing harmonics of the alternating voltage supplied to or output from the power conversion module through a first output capacitor selectively supplying reactive power to the system in accordance with the on / off state of the first switching unit; And
And a controller for controlling on / off of the first switching unit,
The controller comprising:
Wherein the first switching unit is turned off to disconnect the first output capacitor from the output filter if the power conversion module does not perform a charging and discharging operation, And to connect said first output capacitor to said output filter. delete 16. The method of claim 15,
Wherein the output filter comprises:
The first output capacitor;
One or more second output capacitors connected in parallel to the first output capacitor;
The first switching unit selectively connecting the first output capacitor to the output filter; And
And one or more second switching units for selectively coupling the one or more second output capacitors to the output filter, respectively. 18. The method of claim 17,
The controller comprising:
And determines the number of output capacitors to be connected to the output filter among the first and second output capacitors according to the amount of reactive power required in the system.

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