JP6398414B2 - Power storage system, power conversion device, self-sustaining operation system, and power storage system control method - Google Patents

Description

  The present invention relates to a power storage system, a power conversion device, a self-sustained operation system, and a control method for the power storage system.

  In recent years, distributed power sources such as wind power generators and solar power generators have become widespread.

  The distributed power supply can be connected to the commercial power system during normal operation and connected to the commercial power system, and can be temporarily disconnected (separated) from the commercial power system and operated independently during a power failure.

  Since such a distributed power source has a large fluctuation in the amount of power generation due to weather conditions, various techniques for enabling stable power supply have been developed (see, for example, Patent Document 1).

JP 2007-1224797 A

  Under such circumstances, a self-sustained operation system has been developed that uses a power storage unit such as a storage battery or a flywheel to stabilize a large fluctuation power generated by a distributed power source.

  However, such a self-sustained operation system has a difference in current when charging or discharging each power storage unit due to variations in characteristics of equipment such as transformers and power storage units provided in the self-sustained operation system or changes with time. The power storage unit may not be used evenly, for example, or the charging rate may be different, and the usage efficiency of the power storage unit may be reduced. In that case, there is a possibility that fluctuations in the power generation amount of the distributed power source cannot be fully absorbed.

  For this reason, in a self-sustained operation system using such a power storage unit, a technique for improving the utilization efficiency of the power storage unit is required.

  The present invention has been made in view of such problems, and in a self-sustained operation system using a power storage unit, a power storage system that can more evenly use a plurality of power storage units used in a self-sustained operation system, One object is to provide a power conversion device, a self-sustaining operation system, and a control method for an electric power storage system.

One of the means for solving the above problem is a power storage system having a plurality of power storage devices that exchange power with an AC bus, the power storage device comprising: a power storage unit; and A power conversion unit that charges and discharges power between an AC bus and the power storage unit; and a control unit that controls charging and discharging of the power conversion unit, the control unit charging the power storage unit The power conversion unit is controlled such that the frequency of the AC voltage of the power conversion unit is higher as the rate is higher than a reference charging rate calculated from each charging rate of the plurality of power storage units, and the power The power conversion unit is controlled such that the frequency of the AC voltage is lower as the charging rate of the storage unit is lower than the reference charging rate, and the delayed reactive power or the delayed reactive current output by the power converting unit is greater than a predetermined value. The higher the AC voltage Controls the power conversion unit so as to reduce, as the lagging reactive power or lagging reactive current is less than the predetermined value, controlling said power conversion unit such that the amplitude increases of the alternating voltage.

  In addition, the problems disclosed by the present application and the solutions thereof will be clarified by the description in the column of the embodiment for carrying out the invention and the description of the drawings.

  ADVANTAGE OF THE INVENTION According to this invention, in the self-sustained operation system using an electric power storage part, it becomes possible to improve the utilization efficiency of an electric power storage part.

It is a figure which shows the structure of an independent operation system. It is a figure which shows the function of a storage battery system control apparatus. It is a figure which shows the function of a power converter. It is a figure which shows a frequency regulator. It is a figure which shows a voltage regulator. It is a figure explaining a mode that a storage battery system balances electric power. It is a figure explaining a mode that a storage battery system balances electric power. It is a figure explaining a mode that a storage battery system balances electric power. It is a figure explaining a mode that a storage battery system balances electric power. It is a flowchart which shows the flow of control of a storage battery system. It is a figure which shows the function of a storage battery system control apparatus. It is a figure which shows the example of a control result of a storage battery system. It is a figure which shows the function of a storage battery system control apparatus. It is a figure which shows the example of a control result of a storage battery system. It is a figure which shows the function of a storage battery system control apparatus. It is a figure which shows the example of a control result of a storage battery system. It is a figure which shows the function of a storage battery system control apparatus. It is a figure which shows the example of a control result of a storage battery system.

  At least the following matters will become apparent from the description of this specification and the accompanying drawings.

=== Configuration of the autonomous operation system ===
Hereinafter, with reference to FIG. 1, the structure of the autonomous operation system 1000 in one embodiment of the present invention will be described.

  A self-sustained operation system 1000 shown in FIG. 1 includes a power generation facility 300, a load facility 400, and a power storage facility (also referred to as a power storage system) 100 connected to each other via an AC bus 800. In addition, the self-sustained operation system 1000 according to the present embodiment is connected to the commercial power system 900 via the switch 910. However, in this embodiment, the switch 910 is open, and the self-sustained operation system 1000 is temporarily Are disconnected from the commercial power system 900 (disconnected). Self-sustained operation system 1000 may be always disconnected from commercial power grid 900 without being linked to commercial power grid 900.

  The power generation facility 300 includes a transformer 331 and a transformer 330 in addition to a wind power generator 321 and a solar power generator 322 as the power generation device 320.

  Transformer 330 connects switch 910 and AC bus 800. A plurality (two in FIG. 1) of transformers 331 are connected to the transformer 330 in parallel. A wind power generator 321 is connected to one transformer 331, and a solar power generator 332 is connected to the other transformer 331. Thereby, the wind power generator 321 and the solar power generator 322 supply AC power to the AC bus 800. Note that the power generation facility 300 may further include a power generation device 320, such as a fuel cell as well as the power generation device 320 in which the power generation amount varies depending on weather conditions, such as the wind power generator 321 and the solar power generator 322. The power generation amount is not affected by the weather conditions, and the current control type power generation device 320 that operates in synchronization with the reference voltage may be included.

  The load facility 400 includes a load device 420 that consumes AC power supplied from the AC bus 800, a transformer 430, and a switch 410.

  Transformer 430 is connected to AC bus 800 and switch 410. A plurality (two in FIG. 1) of switches 410 are connected to the transformer 430 in parallel. A load device 420 is connected to each switch 410. Thereby, AC power is supplied to the load device 420 from the AC bus 800. Note that the load facility 400 may further include a load device 420.

  The power storage facility 100 includes a plurality (N units (N is a natural number of 2 or more)) of power storage units (power storage devices) 120, a transformer 130 connected to each power storage unit 120, and a storage battery system control device 500. Configured. In the present embodiment, the power storage facility 100 includes three power storage units 120 and three transformers 130 (N = 3).

  Each power storage unit 120 includes a power storage unit capable of storing power and a power converter (power conversion unit, power conversion device) 200 provided for each power storage unit.

  The power storage unit can be realized by a storage battery 121 capable of charging / discharging DC power, a flywheel, a pumped-storage power generation, a capacitor, or the like.

  The power converter 200 charges power supplied from the AC bus 800 to the power storage unit, and discharges power discharged from the power storage unit to the AC bus 800.

  In the present embodiment, a case where a storage battery 121 is used as an example of the power storage unit will be described.

  In that case, the power converter 200 converts AC power supplied from the AC bus 800 into DC power and charges the storage battery 121, takes out DC power from the storage battery 121, converts it to AC power, and discharges it to the AC bus 800. To do.

  Transformer 130 is connected to AC bus 800. Further, the transformer 130 is connected to the storage battery 121 via the power converter 200. Thereby, power converter 200 mutually converts AC power input / output from / to AC bus 800 and DC power charged / discharged by storage battery 121.

  As will be described in detail later, the storage battery system control device 500 includes a first calculation unit that calculates a reference charging rate from each charging rate of a plurality (N units) of storage batteries 121, and a plurality (N units) of power converters 200. And a second arithmetic unit that calculates reference reactive power from reactive power exchanged with AC bus 800.

  Note that the storage battery system control device 500 may calculate the reference reactive current from the reactive currents exchanged between the plurality (N units) of the power converters 200 and the AC bus 800.

  The reference charging rate, the reference reactive current, and the reference reactive power will be described later.

  Further, the voltage vbase of the AC bus 800 (also referred to as a self-sustained operation system bus voltage) is input to the storage battery system control device 500.

  Then, the storage battery system control device 500 includes a frequency correction signal Δfn for adjusting the frequency of the AC voltage output from the n-th (n is a natural number of 1 to N) power converter 200, and an amplitude for adjusting the amplitude. A correction signal ΔVn is generated and output to the nth power converter 200.

  In addition, the self-sustained operation system 1000 according to the present embodiment is configured such that each power converter 200 has the function of the storage battery system control device 500, or any one power converter 200 has the function. It is good also as a structure which does not provide the storage battery system control apparatus 500 by comprising.

=== Storage System Control Device ===
Hereinafter, with reference to FIG. 2, the storage battery system control apparatus 500 in this embodiment is demonstrated.

  The storage battery system control device 500 includes the n-th power converter 200 so that the amplitude and frequency of the AC voltage output from each power converter 200 to the AC bus 800 via the transformer 130 approach a predetermined rated value. Output an amplitude correction signal ΔVn and a frequency correction signal Δfn.

In FIG. 2, the independent operation system bus voltage command | Vbase | ^* indicates the rated value of the effective value of the AC voltage in the AC bus 800. The autonomous operation system bus voltage command | Vbase | ^* is, for example, 6.6 kilovolts.

Reference frequency fbase ^* indicates the rated value of the frequency of the AC voltage in AC bus 800. The reference frequency fbase ^* is, for example, 50 hertz.

  Storage battery system control device 500 acquires voltage vbase of AC bus 800. The effective value calculation unit 520 obtains an effective value | vbase | from vbase, and inputs the effective value | vbase | to the addition unit 536.

  On the other hand, the storage battery system control device 500 acquires the reactive powers Q1 to QN output from the respective power converters 200, and calculates the reference reactive power (second arithmetic unit). In the present embodiment, the adding unit 530 calculates the total value of Q1 to QN, and the multiplication and division unit 531 divides this total value by N to determine the average value of the reactive powers Q1 to QN as the reference reactive power.

Thereafter, the adder 532 obtains the difference between the reference reactive power and the reactive power Qn, the reactive power regulator 534 multiplies the difference by a constant, and the adder 535 causes the autonomous system bus voltage command | Vbase | The sum with ^* is calculated. A difference between this sum and the effective value | vbase | of the voltage of the AC bus 800 is calculated by the adding unit 536.

  Then, the voltage control unit 537 performs predetermined PI control on the difference calculated by the adding unit 536, thereby generating an amplitude correction signal ΔVn. The storage battery system control device 500 outputs the amplitude correction signal ΔVn to the corresponding nth power converter 200.

  For this reason, the amplitude correction signal ΔVn becomes a smaller value as the reactive power Qn output from the n-th power converter 200 is relatively larger than the variations in Q1 to QN, and the reactive power Qn becomes Q1 to QN. The amplitude correction signal ΔVn becomes a larger value as it is relatively smaller with respect to the variation of.

  In addition, when the storage battery system control apparatus 500 acquires the reactive current output from each power converter 200, the storage battery system control apparatus 500 calculates a reference reactive current from each of these reactive currents. In this case, the adding unit 530 obtains the total value of the reactive currents, and the multiplication / division unit 531 divides the total value by N to obtain the average value of the reactive currents as the reference reactive current.

  On the other hand, when the storage battery system control apparatus 500 acquires the voltage vbase of the AC bus 800, the frequency detection unit 501 obtains the frequency fbase of the vbase and inputs the fbase to the addition unit 502.

Adder 502 obtains the difference between the rated value fbase ^* (50 hertz) of the frequency of the AC voltage in AC bus 800 and fbase. The frequency control unit 503 performs predetermined PI control on the difference between fbase ^* and fbase and outputs the result.

  On the other hand, the storage battery system control apparatus 500 acquires the charging rates SOC1 to SOCN from the storage batteries 121, respectively, and calculates the reference charging rate (first calculation unit). In the present embodiment, the adding unit 511 calculates the total value of SOC1 to SOCN, and the multiplication and division unit 512 divides this total value by N, thereby determining the average value of the charging rates SOC1 to SOCN as the reference charging rate.

  Thereafter, the adding unit 513 obtains a difference between the reference charging rate and the charging rate SOCn, the proportional control unit 514 multiplies the difference by a constant, and the adding unit 515 makes a difference from the output value of the frequency control unit 503. Is calculated. The storage battery system control device 500 generates the difference calculated by the adding unit 515 as the frequency correction signal Δfn and outputs it to the corresponding nth power converter 200.

  For this reason, as the charging rate SOCn of the nth storage battery 121 is relatively large with respect to the variation in SOC1 to SOCN, the frequency correction signal Δfn becomes a larger value, and the charging rate SOCn becomes smaller than the variation in SOC1 to SOCN. The smaller the frequency, the smaller the frequency correction signal Δfn.

=== Power Converter ===
Hereinafter, the power converter 200 in the present embodiment will be described with reference to FIGS. 3 to 5 illustrate the nth power converter 200.

  The power converter 200 includes a main circuit unit 210, an output detection unit 220, a droop control unit 230, a frequency control unit 240, a voltage calculation unit 250, a voltage control unit 260, and a voltage command unit 270. Configured. Among these, the droop control unit 230, the frequency control unit 240, the voltage calculation unit 250, the voltage control unit 260, and the voltage command unit 270 constitute a control unit 280.

<Main circuit section>
Main circuit unit 210 is a circuit that mutually converts electric power exchanged with storage battery 121 and electric power exchanged with AC bus 800. Specifically, the main circuit unit 210 is a circuit that mutually converts DC power and AC power.

<Output detector>
The output detection unit 220 is a circuit that detects the AC current in and AC voltage vn for three phases that the main circuit unit 210 exchanges with the AC bus 800. The output detection unit 220 according to this embodiment includes an alternating current detection unit 221 and an alternating voltage detection unit 222. The alternating current detection unit 221 detects the alternating current in of each phase, and the alternating voltage detection unit. 222 detects the AC voltage vn of each phase.

<Droop control unit>
The droop control unit 230 includes an AC / DC conversion unit 231, a frequency regulator 232, and a voltage regulator 233.

  The AC / DC converter 231 performs dq conversion on the three-phase AC current in detected by the AC current detector 221 by using the reference phase angle θ, and d-axis component (effective current component) Id and q-axis component ( Reactive current component) Iq.

  In the present embodiment, the d-axis component Id of the alternating current in is determined to take a positive value when the storage battery 121 is discharged. That is, it takes a positive value when an effective current component of alternating current flows from the main circuit unit 210 toward the transformer 130. Therefore, when the storage battery 121 performs charging, the d-axis component Id of the alternating current in takes a negative value. That is, when an effective current component of alternating current flows from the transformer 130 toward the main circuit unit 210, the negative value is taken.

  The q-axis component Iq of the alternating current in is determined to take a positive value when the phase of the alternating current in output from the main circuit unit 210 is delayed with respect to the phase of the alternating voltage vn. Therefore, when the phase of the alternating current in output from the main circuit unit 210 is advanced with respect to the phase of the alternating voltage vn, the q-axis component Iq of the alternating current in takes a negative value.

The frequency adjuster 232 outputs a frequency adjustment signal df for adjusting the frequency of the AC voltage vn output from the main circuit unit 210 according to the d-axis component Id of the AC current in. As will be described in detail later, the frequency adjustment signal df is added to the reference frequency f0 ^* of the AC voltage vn (50 Hz in this embodiment), and then the main circuit as a frequency command value for controlling the frequency of the AC voltage vn. Input to the unit 210.

  As shown in FIG. 4, the frequency adjuster 232 is configured to have a droop characteristic. Therefore, the frequency adjuster 232 determines the frequency of the AC voltage vn output from the main circuit unit 210 when the effective current component (Id) of the AC current in is a positive value (when the storage battery 121 is discharged). The frequency adjustment signal df is set to a negative value so as to adjust in a decreasing direction, and the greater the effective current component (Id) of the alternating current in, the smaller the frequency adjustment signal df is (the absolute value is larger). To output.

  The frequency adjuster 232 increases the frequency of the AC voltage vn output from the main circuit unit 210 when the effective current component (Id) of the AC current in is negative (when the storage battery 121 is charged). The frequency adjustment signal df is set to a positive value so as to adjust in the direction. The smaller the effective current component (Id) of the alternating current in (the larger the absolute value), the larger the frequency adjustment signal df (the absolute value is Output a larger value).

The voltage regulator 233 outputs a voltage adjustment signal dV for adjusting the amplitude of the AC voltage vn output from the main circuit unit 210 according to the q-axis component Iq of the AC current in. As will be described in detail later, the voltage adjustment signal dV is added as a voltage command value for controlling the amplitude of the AC voltage vn after being added to the output terminal voltage amplitude command | Vn | ^* which is the reference voltage of the AC voltage vn. Input to the circuit unit 210.

  As shown in FIG. 5, the voltage regulator 233 is configured to have a droop characteristic. For this reason, the voltage regulator 233 determines that the reactive current component (Iq) of the alternating current in is a positive value (when the phase of the alternating current in output from the main circuit unit 210 is delayed with respect to the phase of the alternating voltage vn). ), The voltage adjustment signal dV is set to a negative value so as to adjust the amplitude of the AC voltage vn output from the main circuit unit 210 in a decreasing direction, and the reactive current component (Iq) of the AC current in is larger (delayed). As the reactive current increases, the voltage adjustment signal dV is output as a smaller negative value (absolute value is larger).

  Further, the voltage regulator 233 has a negative value of the reactive current component (Iq) of the alternating current in (when the phase of the alternating current in output from the main circuit unit 210 is advanced with respect to the phase of the alternating voltage vn). The voltage adjustment signal dV is set to a positive value so that the amplitude of the AC voltage vn output from the main circuit unit 210 is increased, and the reactive current component (Iq) of the AC current in is smaller (absolute value). As the advance reactive current increases, the voltage adjustment signal dV is output with a larger value (a value with a larger absolute value).

<Frequency control unit>
The frequency control unit 240 includes an adding unit 241, an adding unit 242, and a VCO (Voltage Controlled Oscillator) 243.

The adding unit 241 adds the frequency adjustment signal df generated by the droop control unit 230 to the reference frequency f0 ^* (50 Hz in this embodiment) of the AC voltage vn.

  The adding unit 242 further adds the frequency correction signal Δfn generated by the storage battery system control device 500 to the added value by the adding unit 241 to generate the internal frequency f.

  For this reason, the internal frequency f decreases as the effective current component (Id) of the alternating current in increases, when the storage battery 121 is discharged. Further, when the storage battery 121 is being charged, it increases as the effective current component (Id) of the alternating current in increases.

  The internal frequency f increases as the charging rate SOCn of the storage battery 121 is larger than the average value of SOC1 to SOCN, and decreases as the charging rate SOCn is smaller than the average value of SOC1 to SOCN.

The VCO 243 is a voltage controlled oscillator. The VCO 243 outputs a sine wave signal of the a-phase reference signal Sa and the c-phase reference signal Sc whose frequency is the internal frequency f and whose amplitude is | Vn | ^* .

<Voltage calculator>
The voltage calculation unit 250 includes an AC / DC conversion unit 251, filter circuits 252 and 253, square calculation units 254 and 255, an addition unit 256, and a square root calculation unit 257.

The AC / DC conversion unit 251 receives the AC voltage vn for the three phases output from the main circuit unit 210, and the AC / DC conversion unit 251 obtains the AC voltage vn by dq conversion using the reference phase angle θ. A d-axis component (voltage Vd) and a q-axis component (voltage Vq) are output. Further, the harmonic components are removed from the voltage Vd and the voltage Vq by the filter circuits 252 and 253, respectively, squared by the square calculation units 254 and 255, and then added by the addition unit 256. The square root calculator 257 takes the square root of the output value of the adder 256 and outputs the output terminal voltage fundamental wave positive phase Peak value | Vn | = √ (Vd ² + Vq ² ).

<Voltage control unit>
The voltage control unit 260 is a circuit including an addition unit 261, an addition unit 262, an addition unit 263, and a voltage adjustment unit 264.

  Adder 261 adds voltage adjustment signal dV generated by droop controller 230 to voltage correction signal ΔVn generated by storage battery system controller 500.

The adding unit 262 adds the addition result of the adding unit 261 with the output terminal voltage amplitude command | Vn | ^* that is the reference voltage of the AC voltage vn.

  The adding unit 263 obtains a difference between the addition result of the adding unit 262 and the output terminal voltage fundamental wave positive phase Peak value | Vn | calculated by the voltage calculating unit 250.

  The voltage adjustment unit 264 outputs a voltage deviation dVn obtained by multiplying the difference value of the addition unit 263 by a predetermined proportional gain.

  For this reason, when the phase of the alternating current in output from the main circuit unit 210 is delayed with respect to the phase of the alternating voltage vn, the voltage deviation dVn decreases as the delay increases, and the phase of the alternating current in changes to the alternating current in. When the phase is advanced with respect to the phase of the voltage vn, the larger the advance, the larger the value.

  Further, the voltage deviation dVn decreases as the delayed reactive power exchanged with the AC bus 800 by the main circuit unit 210 is larger than the average value, and increases as the delayed reactive power is smaller than the average value.

  The delayed reactive power represents reactive power when the phase of the alternating current in output from the main circuit unit 210 is delayed with respect to the phase of the alternating voltage vn.

  The advanced reactive power represents reactive power when the phase of the alternating current in output from the main circuit unit 210 is advanced with respect to the phase of the alternating voltage vn.

  When the storage battery system control device 500 acquires the reactive currents output from the respective power converters 200, the voltage deviation dVn is the average value of the delayed reactive currents that the main circuit unit 210 exchanges with the AC bus 800. The larger the value, the smaller the value becomes, and the smaller the delayed reactive current becomes, the larger the value becomes.

  The delayed reactive current is a component of the alternating current in that is delayed by 90 ° with respect to the phase of the alternating voltage vn when the phase of the alternating current in output from the main circuit unit 210 is delayed with respect to the phase of the alternating voltage vn. Represents.

  The leading reactive current is a component of the alternating current in that is advanced by 90 ° with respect to the phase of the alternating voltage vn when the phase of the alternating current in output from the main circuit unit 210 is advanced with respect to the phase of the alternating voltage vn. Represents.

<Voltage command section>
The voltage command unit 270 includes multipliers 271, 272, adders 273, 274, 275, and a PWM signal generator 276.

  Multipliers 271 and 272 output a-phase reference signal Sa and c-phase reference signal Sc (multiplied by dVn) respectively multiplied by voltage deviation dVn.

The adder 273 outputs an a-phase voltage command value via ^* = (1 + dVn) · Sa obtained by adding the a-phase reference signal Sa multiplied by dVn to the a-phase reference signal Sa. On the other hand, the adder 274 outputs a c-phase voltage command value vic ^* = (1 + dVn) · Sc obtained by adding the c-phase reference signal Sc multiplied by dVn to the c-phase reference signal Sc. Further, the adder 275 outputs the b-phase voltage command value vib ^* =-(vna ^* + vnc ^* ) obtained by adding the a-phase voltage command value via ^* and the c-phase voltage command value vic ^* and inverting it. Yes.

PWM signal generating unit 276, via ^*, vib ^*, has a duty ratio that varies depending on the respective peak value of ^{vic *, via *, vib *} , positive and negative are inverted in accordance with the respective positive and negative vic ^* This is converted into a PWM signal and output.

  This PWM signal is input to the main circuit unit 210. The main circuit unit 210 outputs an alternating voltage vn having the above-described frequency and amplitude indicated by the PWM signal.

  In this way, the control unit 280 (the droop control unit 230, the frequency control unit 240, the voltage calculation unit 250, the voltage control unit 360, and the voltage command unit 270) according to the present embodiment controls the main circuit unit 210.

=== Balance control ===
Here, control performed by the power storage facility 100 according to the present embodiment in order to improve the utilization efficiency of the plurality of storage batteries 121 will be described with reference to FIGS. 6 to 10.

  As shown in FIG. 6, when the self-sustaining operation system 1000 is disconnected from the commercial power system 900 and performs self-sustaining operation, each storage battery unit 120 controls the amplitude and phase of the AC voltage individually. The AC power supplied to the load device 420 is shared.

  In FIG. 6, the first storage battery unit 120 (indicated as PCS1 in FIG. 6) outputs an AC voltage v1 having an amplitude V1 and a phase δ1 to share AC power (active power P1, reactive power Q1), and the second storage battery unit. 120 (shown as PCS2 in FIG. 6) outputs AC voltage v2 having amplitude V2 and phase δ2 to share AC power (active power P2, reactive power Q2), and AC power (active power Pr, reactive power) to load device 420. The state of supplying power Qr) is shown. The phases δ1 and δ2 are phase differences based on the phase of the AC voltage vr in the load device 420. In FIG. 6, the transformer 130, the transformer 430, and the switch 410 are omitted.

At this time, the output voltage v1 of PCS1, the output voltage v2 of PCS2, and the supply voltage vr of the load device 420 are [Equation 1], respectively.
v1 = V1 · sin (ωt + δ1) (1)
[Equation 2]
v2 = V2 · sin (ωt + δ2) (2)
[Equation 3]
vr = Vr · sin ωt (3)
It becomes.

Also, assuming that the impedance of the transmission / distribution line connected to PCS1 is X1, and the impedance of the transmission / distribution line connected to PCS2 is X2, the active power P1 supplied by PCS1, the reactive power Q1, the effective power P2 supplied by PCS2, Reactive power Q2, respectively,
[Equation 4]
P1 = (V1 · Vr / Xl) · sinδ1 (4)
[Equation 5]
Q1 = (V1 · Vr / X1) · cos δ1− (V1 ² / X1) (5)
[Equation 6]
P2 = (V2 · Vr / X2) · sinδ2 (6)
[Equation 7]
Q2 = (V2 · Vr / X2) · cos δ2− (V2 ² / X2) (7)
It is known to be given in

  From formulas (4) and (6), the active powers P1 and P2 are proportional to the phase differences δ1 and δ2 with respect to the load device 420. For example, when P1> P2> 0, δ1> δ2> 0 and the voltage Is as shown in FIG.

  In such a case, when the power converter 200 according to the present embodiment is discharging the storage battery 121, the droop control unit 230 has a smaller negative value as the effective current component (Id) of the alternating current in is larger. By outputting the frequency adjustment signal df having a larger absolute value, the main circuit unit 210 is controlled so that the frequency of the AC voltage vn output from the main circuit unit 210 is reduced.

  Therefore, for example, when the active powers P1 and P2 output by PCS1 and PCS2 in FIG. 6 are P1> P2> 0, the amount of decrease in the frequency of the AC voltage v1 output by PCS1, as shown in FIG. Since the amount of decrease in the frequency of the AC voltage v2 output from the PCS2 is larger, the difference between δ1 and δ2 is reduced, and the balance is achieved when the phase difference with the load device 420 becomes δ ′.

However, in this state, since the frequency of the AC voltage v1 output by the PCS1 and the frequency of the AC voltage v2 output by the PCS2 are both reduced, the power converter 200 according to the present embodiment is from the storage battery system control device 500. The frequency of the AC voltages v1 and v2 is controlled so as to approach the reference frequency fbase ^* (50 Hz) by the output frequency correction signal Δfn.

  At this time, as described above, the frequency correction signal Δfn acts to increase the frequency of the alternating voltage vn as the charging rate of the storage battery 121 is relatively higher than the charging rate of the other storage battery. As the charging rate of the storage battery 121 is relatively lower than the charging rate, the frequency of the AC voltage vn is decreased.

  For example, the frequency correction signal Δfn acts to increase the frequency of the AC voltage vn as the charging rate of the storage battery 121 is higher than the average value, and as the charging rate of the storage battery 121 is lower than the average value, the AC voltage It works to decrease the frequency of vn.

  As shown in FIG. 8, when the storage battery 121 is being discharged, if the frequency of the AC voltage vn increases, the phase difference δ with the load device 420 increases, and therefore, as shown in Expression (4) and Expression (6). Thus, the active power flowing out from the storage battery 121 increases.

  In this way, the amount of discharge from the storage battery 121 having a relatively high charging rate is increased. On the other hand, the amount of discharge from the storage battery 121 having a relatively low charging rate decreases.

  For this reason, the charge rate of the storage battery 121 in the power storage facility 100 is controlled to be uniform.

  Thus, as the control by the frequency adjustment signal df and the control by the frequency correction signal Δfn are synergistically performed, the share of AC power supplied to the load device 420 by each power storage unit 120 and each power storage unit 120 The charging rates of the storage batteries 121 included in the battery are both equalized.

  In this way, the power converter 200 according to the present embodiment can make the plurality of storage batteries 121 used in the self-sustaining operation system 1000 available more evenly.

  Similarly, when the storage battery 121 is being charged, the power converter 200 according to the present embodiment has a larger effective current component (Id) of the alternating current in (as described above, Id is a negative value). Therefore, as the absolute value increases, the droop control unit 230 outputs the frequency adjustment signal df having a larger positive value (a larger absolute value), whereby the alternating current output from the main circuit unit 210 is output. The main circuit unit 210 is controlled so that the frequency of the voltage vn is increased.

  Therefore, for example, when the active powers P1 and P2 (negative values) output by PCS1 and PCS2 in FIG. 6 are P1 <P2 <0 (| P1 |> | P2 |), as shown in FIG. Since the increase amount of the frequency of the AC voltage v1 output from the PCS1 is larger than the increase amount of the frequency of the AC voltage v2 output from the PCS2, the difference between δ1 and δ2 is reduced as in the discharge, and the load device 420 Balance when the phase difference between and becomes δ '.

Also in this case, the power converter 200 according to the present embodiment causes the frequencies of the AC voltages v1 and v2 to approach the reference frequency fbase ^* (50 Hz) by the frequency correction signal Δfn output from the storage battery system control device 500. To control.

  At this time, as described above, the frequency correction signal Δfn acts to increase the frequency of the alternating voltage vn as the charging rate of the storage battery 121 is relatively higher than the charging rate of the other storage battery. As the charging rate of the storage battery 121 is relatively lower than the charging rate, the frequency of the AC voltage vn is reduced.

  As shown in FIG. 9, when the storage battery 121 is being charged, if the frequency of the AC voltage vn increases, the phase difference δ with the load device 420 decreases, and therefore, the equations (4) and (6) are obtained. As such, the effective power flowing into the storage battery 121 decreases.

  In this way, the amount of charge to the storage battery 121 having a relatively high charging rate is reduced. On the other hand, the amount of charge to the storage battery 121 having a relatively low charging rate increases.

  For this reason, the charge rate of the storage battery 121 in the power storage facility 100 is controlled to be uniform.

  Thus, as the control by the frequency adjustment signal df and the control by the frequency correction signal Δfn are synergistically performed, the share of AC power supplied to the load device 420 by each power storage unit 120 and each power storage unit 120 The charging rates of the storage batteries 121 included in the battery are both equalized.

  In this way, the power converter 200 according to the present embodiment can make the plurality of storage batteries 121 used in the self-sustaining operation system 1000 available more evenly.

=== Flow of control ===
Next, a control flow in the power storage facility 100 according to the present embodiment will be described with reference to FIG.

  First, the output detection unit 220 in each power converter 200 detects the AC current in and AC voltage vn for three phases output from the main circuit unit 210 (S1000).

Then, the droop control unit 230, the frequency control unit 240, and the voltage command unit 270 in each power converter 200 control the frequency of the AC voltage vn according to the effective current component Id of the AC current in (S1010). Specifically, first, the droop control unit 230 decreases the frequency of the alternating voltage vn as the effective current component Id of the alternating current in increases when the storage battery 121 is discharged, and the effective current component Id increases when the storage battery 121 is charged. The frequency adjustment signal df is output so as to increase the frequency of the AC voltage vn. The frequency control unit 240 adds the frequency adjustment signal df generated by the droop control unit 230 to the reference frequency f0 ^* (50 Hz in this embodiment) of the AC voltage vn to obtain the internal frequency f, and the voltage command unit 270. Outputs to the main circuit unit 210 a PWM signal for setting the frequency of the alternating voltage vn to the internal frequency f.

The storage battery system control device 500, the frequency control unit 240 in each power converter 200, and the voltage command unit 270 control the frequency of the AC voltage vn output from the main circuit unit 210 according to the charging rate SOC of the storage battery 121. (S1020). Specifically, storage battery system control device 500 first generates frequency correction signal Δfn based on charging rates SOC1 to SOCN of each storage battery 121. Then, the frequency correction signal Δfn generated by the storage battery system control device 500 is added to the reference frequency f0 ^* (50 Hz in this embodiment) of the AC voltage vn to obtain the internal frequency f, and the voltage command unit 270 receives the AC voltage vn The PWM signal for setting the frequency to the internal frequency f is output to the main circuit unit 210.

The droop control unit 230, the voltage calculation unit 250, the voltage control unit 260, and the voltage command unit 270 in each power converter 200 control the amplitude of the AC voltage vn according to the reactive current component Iq of the AC current in (S1030). ). Specifically, the droop control unit 230 first decreases the amplitude of the AC voltage vn when the reactive current component (Iq) is a positive value, and reduces the AC voltage vn when the reactive current component (Iq) is a negative value. The voltage adjustment signal dV is output so as to increase the amplitude. Then, the voltage calculation unit 250 obtains the output terminal voltage fundamental wave positive phase Peak value | Vn |, and the voltage control unit 260 outputs the output terminal voltage fundamental wave positive phase Peak value | Vn | and the output terminal voltage amplitude command | Vn | ^The voltage difference dVn is obtained by adding the voltage adjustment signal dV generated by the droop control unit 230 to the difference between ^* and the voltage command unit 270 is a PWM for increasing the amplitude of the AC voltage vn by the voltage deviation dVn. The signal is output to the main circuit unit 210.

In addition, the storage battery system control device 500, the voltage control unit 260 in each power converter 200, and the voltage command unit 270 are connected to the AC voltage vn output from the main circuit unit 210 according to the reactive power output from each power converter 200. Is controlled (S1040). Specifically, storage battery system control device 500 first generates voltage correction signal ΔVn based on reactive power Q1 to QN output from each power converter 200. Then, the voltage control unit 260 adds the voltage correction signal ΔVn generated by the storage battery system control apparatus 500 to the difference between the output terminal voltage fundamental wave positive phase Peak value | Vn | and the output terminal voltage amplitude command | Vn | ^*. Thus, the voltage deviation dVn is obtained, and the voltage command unit 270 outputs a PWM signal for increasing the amplitude of the alternating voltage vn to the voltage deviation dVn to the main circuit unit 210.

  In addition, since the electrical storage equipment 100 according to the present embodiment executes the above-described processes (S1000 to S1040) in parallel, the order of the processes is for convenience of explanation, and the order of the processes is different. May be.

=== Example ===
Next, an example of the independent operation system 1000 will be described.

  In this embodiment, the leakage inductance of the transformer 130 connected to each of the three power storage units 120 included in the self-sustaining operation system 1000 (hereinafter, each storage battery unit 120 is also referred to as Unit 1, Unit 2, Unit 3), Assume that they are 10%, 7.5%, and 5%, respectively.

  In addition, the charging rates of the storage batteries 121 included in the No. 1 to No. 3 units 120 are 70%, 65%, and 60%, respectively, in the initial state.

  As described above, each power converter 200 included in each unit 120 includes the droop control unit 230 having the droop characteristics as illustrated in FIGS. 4 and 5. Therefore, when the output terminal effective current (Id) of the power storage unit 120 is positive (discharge), the frequency is decreased, and when the output terminal reactive current (Iq) is positive (delayed), the output terminal voltage is decreased. Controlled.

  By performing such control, each power storage unit 120 can autonomously share active power and reactive power.

  Moreover, as described above, the storage battery system control device 500 acquires the voltage vbase of the AC bus 800.

Then, as shown in FIG. 11, the storage battery system control device 500 has a predetermined value for the difference between the effective value | vbase | obtained from the voltage vbase of the AC bus 800 and the independent operation system bus voltage command | Vbase | ^* . By performing PI control, an amplitude correction signal ΔVn is generated, and this amplitude correction signal ΔVn is output to the corresponding power converter 200.

Further, the storage battery system control device 500 performs predetermined PI control on the difference between the frequency fbase of the voltage vbase of the AC bus 800 and the reference frequency fbase ^* to generate a frequency correction signal Δfn, and this frequency correction signal Δfn Is output to the power converter 200.

  At this time, when the plurality of power storage units 120 are performing constant voltage constant frequency control with the output of the power generation device 320 and the load device 420 being zero, the output terminal current in of the power storage unit 120 is zero. Thus, by the droop control of the power converter 200, the frequency of the AC bus 800 is maintained at the reference frequency (for example, 50 Hz), and the voltage is maintained at the reference voltage (for example, 1 [pu]).

  Then, as shown in FIG. 12, when the power generation device 320 starts output (power factor 1, only output for the effective portion) from this state, the load device 420 is not yet connected, so the output of the power generation device 320 is The storage battery 121 is fully charged.

  Therefore, the output end effective current in of each power storage unit 120 is negative (charged). In the example shown in FIG. 12, each is −0.3 [pu].

  Then, the frequency of AC voltage vn output from each power converter 200 is controlled to increase by the droop characteristic of each power converter 200. And the effective current in between the electrical storage units 120 is adjusted autonomously, and each electrical storage unit 120 comes to share an active electric power (charge amount) equally. In the example shown in FIG. 12, each is −0.3 [pu].

By the above control, the frequency of the AC voltage vn output from each power storage unit 120 increases, so the frequency of the AC bus 800 also increases, but the storage battery system control device 500 measures the frequency of vbase as described above, The frequency correction signal Δfn is output so as to approach the reference frequency fbase ^* (50 Hz).

Each power storage unit 120 maintains the sharing ratio of the effective current (charge amount) because the frequency of the AC voltage vn is lowered when the frequency correction signals Δf _{1 to} Δf ₃ (negative values, all the same value) are input. As it is, the frequency of the AC bus 800 is set to 50 Hz.

  Subsequently, as shown in FIG. 12, it is assumed that a load device 420 (having a delay power factor of 0.85) that consumes more power than the power generation device 320 outputs is input.

  In this case, since the shortage of the power consumption of the load device 420 is discharged from the storage battery 121, the output end effective current in of each power storage unit 120 is positive (discharged). In the example shown in FIG. 12, each is +0.3 [pu].

  Also in this case, since the active current in is adjusted between the power storage units 200 and autonomous control is performed so as to share the active power amount (discharge amount) equally, the frequency of the AC bus 800 is set to 50 Hz. The

  In addition, when the load device 420 is turned on, each power storage unit 120 also supplies an invalid (delayed) amount of power to the load device 420. For this reason, a reactive current flows in the delay direction at the output end of each power storage unit 120.

  Then, because the droop characteristic of each power storage unit 120 is controlled so that the power storage unit 120 having a larger delay reduces the amplitude of the AC voltage vn, the share of the reactive current (delay) output from each power storage unit 120 is controlled. Is controlled to be uniform.

  In the present embodiment, as described above, the leakage inductance of the transformer 130 is 10%, 7.5%, and 5%, respectively. Therefore, as shown in FIG. It depends on the leakage inductance of each transformer 130.

As a result of the above control, the amplitude of the AC voltage vn output from each power storage unit 120 decreases, so the voltage of the AC bus 800 decreases. However, as described above, the storage battery system control device 500 measures the effective value of vbase. The voltage correction signal ΔVn is output so as to approach the self-sustained operation system bus voltage command | Vbase | ^* . In this way, the reduced voltage of the AC bus 800 is set to 1 [pu].

  As described above, the self-sustained operation system 1000 according to the present embodiment can maintain the voltage and frequency of the AC bus 800 and adjust the supply and demand.

  As described above, the storage battery system control device 500 according to the present embodiment acquires the voltage vbase of the AC bus 800 and the SOC1 to SOCN of each storage battery 121 as shown in FIG.

  That is, storage battery system control apparatus 500 obtains charging rates SOC1 to SOCN from each storage battery 121 to calculate a reference charging rate, and multiplies the difference between this reference charging rate and charging rate SOCn by an addition unit 515. Generates a frequency correction signal Δfn and outputs it to the corresponding nth power converter 200.

In this way, storage battery system control device 500 weights frequency correction signals Δf _{1 to} Δf ₃ transmitted to each power storage unit 120 according to the SOC deviation of each storage battery 121.

  The power converter 200 controls the main circuit unit 210 to increase the frequency of the AC voltage vn as the charging rate of the storage battery 121 is higher than the average charging rate, and the charging rate of the storage battery 121 is higher than the average charging rate. Is lower, the main circuit unit 210 is controlled to decrease the frequency of the AC voltage vn.

  Thereby, for example, the power converter 200 of the first unit whose SOC is higher than the average value discharges more when discharging and charges less when charging.

  Accordingly, as shown in FIG. 14, the SOC (charge rate) of each storage battery 121 is made uniform while operating the self-sustained operation system 1000, so that only a part of the power storage units 120 is discharged or fully charged (full charge). It becomes possible to continue driving for a long time without falling into the process.

  In this way, the power converter 200 according to the present embodiment can make the plurality of storage batteries 121 used in the self-sustaining operation system 1000 available more evenly.

  Next, an example in which the storage battery system control device 500 measures the voltage vbase of the AC bus 800 and the output end reactive power (Q1 to Q3) of each power storage unit 120 as measured values will be described.

In this case, as described above, the storage battery system control device 500 weights the voltage correction signal ΔV _n transmitted to each power storage unit 120 according to the deviation of the output end reactive power of each power storage unit 120.

As shown in FIG. 15, the storage battery system control device 500 acquires the reactive powers Q1 to QN output from the respective power converters 200, and calculates the reference reactive power. The adder 532 calculates the difference between the reference reactive power and the reactive power Qn, the reactive power regulator 534 multiplies the difference by a constant, and the adder 535 causes the autonomous system bus voltage command | Vbase | ^* Is calculated. A difference between this sum and the effective value | vbase | of the voltage of the AC bus 800 is calculated by the adding unit 536.

  Then, the voltage control unit 537 performs predetermined PI control on the difference calculated by the adding unit 536 to generate an amplitude correction signal ΔVn, and the amplitude correction signal ΔVn is converted into the corresponding nth power conversion. Output to the device 200.

  The power converter 200 controls the main circuit unit 210 so that the reactive power transmitted to and received from the AC bus 800 is smaller than the average value of each reactive power by the amplitude correction signal ΔVn, so that the amplitude of the AC voltage vn is reduced. Then, the main circuit unit 210 is controlled to increase the amplitude of the AC voltage vn as the average value is smaller.

  Thereby, even when the characteristic (leakage inductance) of the transformer 130 varies, the share of reactive power can be made uniform as shown in FIG. Therefore, for example, it is possible to reduce a risk that a part of the power storage units 120 bears more reactive current and falls into an overcurrent stop exceeding the rating.

  Next, a case where the storage battery system control device 500 measures the voltage vbase of the AC bus 800, the SOC of each storage battery 121, and the output terminal reactive power (Q1 to Q3) of each storage unit 120 as measurement values will be described. To do.

In this case, as described above, the storage battery system control device 500 weights the frequency correction signals Δf _{1 to} Δf ₃ transmitted to each power storage unit 120 in accordance with the SOC deviation of each storage battery 121, and each power storage unit. The voltage correction signal ΔV _n transmitted to each power storage unit 120 is weighted according to the deviation of the output power reactive power at 120.

  That is, as shown in FIG. 17, the storage battery system control device 500 obtains the voltage vbase of the AC bus 800, the SOC 1 to SOCN of each storage battery 121, and the reactive power Q 1 to QN output from each power converter 200, respectively. Have acquired.

  Storage battery system control apparatus 500 obtains charging rates SOC1 to SOCN from each storage battery 121 to calculate a reference charging rate, and multiplies the difference between this reference charging rate and charging rate SOCn by an addition unit 515. Generates a frequency correction signal Δfn and outputs it to the corresponding nth power converter 200.

In this way, storage battery system control device 500 weights frequency correction signals Δf _{1 to} Δf ₃ transmitted to each power storage unit 120 according to the SOC deviation of each storage battery 121.

Moreover, the storage battery system control apparatus 500 calculates the reference reactive power using the reactive powers Q1 to QN output from the power converters 200, respectively. The adder 532 calculates the difference between the reference reactive power and the reactive power Qn, the reactive power regulator 534 multiplies the difference by a constant, and the adder 535 causes the autonomous system bus voltage command | Vbase | ^* Is calculated. A difference between this sum and the effective value | vbase | of the voltage of the AC bus 800 is calculated by the adding unit 536.

  Then, the voltage control unit 537 performs predetermined PI control on the difference calculated by the adding unit 536 to generate an amplitude correction signal ΔVn, and the amplitude correction signal ΔVn is converted into the corresponding nth power conversion. Output to the device 200.

  Then, the power converter 200 controls the main circuit unit 210 so as to increase the frequency of the alternating voltage vn as the charging rate of the storage battery 121 is higher than the average charging rate by the frequency correction signal Δfn, and the charging rate of the storage battery 121 is increased. Is lower than the average charging rate, the main circuit unit 210 is controlled to decrease the frequency of the AC voltage vn, and the reactive power exchanged with the AC bus 800 by the amplitude correction signal ΔVn is the average value of each reactive power. The main circuit unit 210 is controlled to decrease the amplitude of the AC voltage vn as the value is larger than the value, and the main circuit unit 210 is controlled to increase the amplitude of the AC voltage vn as the value is smaller than the average value.

  Thereby, for example, the power converter 200 having the SOC higher than the average value discharges more at the time of discharging and charges less at the time of charging.

  Therefore, as shown in FIG. 18, the SOC (charge rate) of each storage battery 121 is gradually equalized while operating the self-sustaining operation system 1000, and the storage batteries 121 can be used more evenly. Since only the power storage unit 120 of the power supply unit 120 does not stop discharging or stop charging (full charge), and the reactive power can be shared equally, for example, the characteristics (leakage inductance) of the transformer 130 vary. Even in such a case, since some of the power storage units 120 bear more reactive current and can reduce the risk of over-current stop exceeding the rating, the continuous operation of the independent operation system 1000 can be reduced. It becomes possible to lengthen the time.

  The self-sustained operation system 1000 according to the present embodiment has been described above. However, according to the self-sustained operation system 1000 according to the present embodiment, the utilization efficiency of the storage battery 121 can be further improved.

  In addition, there is no case where some of the power storage units 120 bear a large amount of reactive power, and the risk due to the overcurrent stop of the power storage units 120 is reduced, and the autonomous operation system 1000 can be stabilized.

  In addition, since the charge rates of the plurality of storage batteries 121 can be equalized without interrupting the operation of the independent operation system 1000, it is possible to stably supply power to the load device 420.

  In addition, since some of the power storage units 120 of the plurality of power storage units 120 can be prevented from falling into a discharge termination or a charge termination (full charge) before other power storage units 120, a self-sustained operation system 1000 can be stabilized and long-time operation can be achieved.

  In addition, the self-sustained operation system 1000 according to the present embodiment can also adjust supply and demand and stabilize the self-sustained operation system 1000 without measuring the total load of the load device 420.

  For this reason, a measuring instrument for measuring the load of the load device 420 becomes unnecessary, the cost can be reduced, and the power generation device 320 and the load device 420 can be easily added or deleted.

  In addition, the said embodiment is for making an understanding of this invention easy, and is not for limiting and interpreting this invention. The present invention can be changed and improved without departing from the gist thereof, and the present invention includes equivalents thereof.

  For example, the storage battery system control device 500 or the control unit 280 may be realized using hardware such as an electronic circuit, an electric circuit, or an electronic component, or a computer having a CPU (Central Processing Unit) or a memory, or An integrated circuit such as an ASIC (Application Specific Integrated Circuit) may be realized by executing a program for realizing the functions of the storage battery system control device 500 and the control unit 280 according to the present embodiment.

  In addition, the program can be in the form of being stored in a recording medium such as a CD-ROM or DVD readable by a computer.

DESCRIPTION OF SYMBOLS 100 Power storage equipment 120 Power storage unit 121 Storage battery 130 Transformer 200 Power converter 210 Main circuit part 220 Output detection part 221 AC current detection part 222 AC voltage detection part 230 Droop control part 231 AC / DC conversion part 232 Frequency regulator 233 Voltage regulator 240 Frequency control unit 241 Adder 242 Adder 243 VCO
250 Voltage calculation unit 251 AC / DC conversion unit 252 Filter circuit 253 Filter circuit 254 Square calculation unit 255 Square calculation unit 256 Addition unit 257 Square root calculation unit 260 Voltage control unit 261 Addition unit 262 Addition unit 263 Addition unit 264 Voltage adjustment unit 270 Voltage command unit 271 Multiplier 272 Multiplier 273 Adder 274 Adder 275 Adder 275 Adder 276 PWM signal generator 280 Controller 300 Power generation equipment 320 Power generator 321 Wind power generator 322 Solar power generator 330 Transformer 331 Transformer 400 Load equipment 410 Switch 420 load device 430 transformer 500 storage battery system control device 501 frequency detection unit 502 addition unit 503 frequency control unit 511 addition unit 512 multiplication / division unit 513 addition unit 514 proportional control unit 515 addition unit 520 effective value calculation unit 530 Adder 531 Multiplier / Divider 532 Adder 534 Reactive power controller 535 Adder 536 Adder 537 Voltage controller 800 AC bus 900 Commercial power system 910 Switch 1000 Self-sustained operation system

Claims (8)

A power storage system having a plurality of power storage devices that exchange power with an AC bus,
The power storage device includes:
A power storage unit;
A power conversion unit that charges and discharges power between the AC bus and the power storage unit;
A controller that controls charging and discharging of the power converter,
The controller is
The power conversion unit is configured such that the higher the charging rate of the power storage unit is higher than a reference charging rate calculated from the charging rates of the plurality of power storage units, the higher the frequency of the AC voltage of the power conversion unit is. The power conversion unit is controlled so that the frequency of the AC voltage is lower as the charging rate of the power storage unit is lower than the reference charging rate, and the delayed reactive power or delay output by the power conversion unit is controlled. The power conversion unit is controlled so that the amplitude of the AC voltage is reduced as the reactive current is larger than a predetermined value, and the amplitude of the AC voltage is increased as the delayed reactive power or delayed reactive current is smaller than the predetermined value. And controlling the power conversion unit. The power storage system according to claim 1,
The power storage system according to claim 1, wherein the predetermined value is a reactive current or an average value of reactive power obtained from an alternating current exchanged between the power converter and the alternating current bus. A power storage system having a plurality of power storage devices that exchange power with an AC bus,
The power storage device includes:
A power storage unit;
A power conversion unit that charges and discharges power between the AC bus and the power storage unit;
A controller that controls charging and discharging of the power converter,
The controller is
The power conversion unit is configured such that the higher the charging rate of the power storage unit is higher than a reference charging rate calculated from the charging rates of the plurality of power storage units, the higher the frequency of the AC voltage of the power conversion unit is. The power conversion unit is controlled so that the frequency of the AC voltage is lower as the charging rate of the power storage unit is lower than the reference charging rate, and the delayed reactive power or delay output by the power conversion unit is controlled. The power conversion unit is controlled so that the amplitude of the AC voltage is reduced as the reactive current is larger than a predetermined value, and the amplitude of the AC voltage is increased as the delayed reactive power or delayed reactive current is smaller than the predetermined value. the control the power conversion unit, up about invalid current is larger controls the power conversion unit so that the amplitude decreases the AC voltage, the AC voltage as the reactive current is large advances vibration in Power storage system, characterized in that to control the power conversion unit to be larger. A power storage system having a plurality of power storage devices that exchange power with an AC bus,
The power storage device includes:
A power storage unit;
A power conversion unit that charges and discharges power between the AC bus and the power storage unit;
A controller that controls charging and discharging of the power converter,
The controller is
The power conversion unit is configured such that the higher the charging rate of the power storage unit is higher than a reference charging rate calculated from the charging rates of the plurality of power storage units, the higher the frequency of the AC voltage of the power conversion unit is. And controlling the power conversion unit so that the frequency of the AC voltage is lower as the charging rate of the power storage unit is lower than the reference charging rate,
At the time of discharging the power storage unit, the power conversion unit is controlled such that the frequency of the AC voltage decreases as the effective current component of the AC current exchanged between the power conversion unit and the AC bus increases. When the power storage unit is charged, the power conversion unit is controlled so that the frequency of the AC voltage increases as the effective current component decreases. The power storage system according to any one of claims 1 to 4 ,
The power storage system according to claim 1, wherein the reference charging rate is an average value of charging rates of the plurality of power storage units. A power storage unit;
A power converter having a main circuit unit that charges and discharges power between an AC bus and the power storage unit, and a control unit that controls charging and discharging of the main circuit unit;
The power conversion device in a power storage system comprising a plurality of power storage devices configured to include:
The controller is
The main circuit unit is configured such that the higher the charging rate of the power storage unit is higher than a reference charging rate calculated from the charging rates of the plurality of power storage units, the higher the frequency of the AC voltage of the main circuit unit is. The main circuit unit is controlled such that the frequency of the AC voltage is lower as the charging rate of the power storage unit is lower than the reference charging rate, and the reactive power or delay output from the main circuit unit is controlled. The main circuit unit is controlled so that the amplitude of the AC voltage is reduced as the reactive current is larger than a predetermined value, and the amplitude of the AC voltage is increased as the delayed reactive power or delayed reactive current is smaller than the predetermined value. And controlling the main circuit unit. A power generator for supplying power to the AC bus;
A load device that consumes power supplied from the AC bus;
A plurality of power storage devices that exchange power with the AC bus; and
A self-sustaining operation system comprising:
The power storage device includes:
A power storage unit;
A power conversion unit that charges and discharges power between the AC bus and the power storage unit;
A controller that controls charging and discharging of the power converter,
The controller is
The power conversion unit is configured such that the higher the charging rate of the power storage unit is higher than a reference charging rate calculated from the charging rates of the plurality of power storage units, the higher the frequency of the AC voltage of the power conversion unit is. The power conversion unit is controlled so that the frequency of the AC voltage is lower as the charging rate of the power storage unit is lower than the reference charging rate, and the delayed reactive power or delay output by the power conversion unit is controlled. The power conversion unit is controlled so that the amplitude of the AC voltage is reduced as the reactive current is larger than a predetermined value, and the amplitude of the AC voltage is increased as the delayed reactive power or delayed reactive current is smaller than the predetermined value. And controlling the power converter. Provided with a plurality of power storage devices having a power storage unit, a power conversion unit that charges and discharges power between an AC bus and the power storage unit, and a control unit that controls charge and discharge of the power conversion unit A method for controlling a power storage system, comprising:
The control unit of the power storage device is:
The power conversion unit is configured such that the higher the charging rate of the power storage unit is higher than a reference charging rate calculated from the charging rates of the plurality of power storage units, the higher the frequency of the AC voltage of the power conversion unit is. The power conversion unit is controlled so that the frequency of the AC voltage is lower as the charging rate of the power storage unit is lower than the reference charging rate, and the power conversion unit of the power storage device outputs The power converter is controlled so that the amplitude of the AC voltage decreases as the delay reactive power or the delay reactive current is larger than a predetermined value, and as the delay reactive power or the delay reactive current is smaller than the predetermined value, the AC voltage The method for controlling an electric power storage system, wherein the power conversion unit is controlled so as to increase an amplitude.