JP7293145B2 - MONITORING CONTROL DEVICE, STORAGE BATTERY SYSTEM AND METHOD - Google Patents

Description

TECHNICAL FIELD Embodiments of the present invention relate to a monitoring control device, a storage battery system, and a method.

In recent years, the introduction of safe and clean natural energy sources such as solar power generation and wind power generation is progressing. However, the output of renewable energy is unstable, and it is feared that the introduction of a large amount of renewable energy will adversely affect the voltage and frequency of the power system. Moreover, if the supply of these natural energies greatly exceeds the power demand, the natural energy power generation system will have to be stopped, resulting in a decrease in the utilization rate of the power generation facilities.

Conventionally, stabilization of voltage and frequency in power systems has been handled by governor-free control of generators, LFC (Load Frequency Control) function, load leveling by pumped storage power generation, and the like. However, there were problems such as the problem of insufficient allowance for lowering the generator, the restrictions on the location conditions for the construction of the pumped-storage power plant, and the long construction period.

Therefore, attention is increasing to a large-scale storage battery system using a secondary battery, which has relatively few restrictions on location conditions.

Japanese Patent No. 6026226 JP 2014-171335 A

By the way, the voltages between the battery units (battery panels) connected in parallel in the storage battery system are almost equal. However, when a failure occurs in a certain battery unit, only that battery unit may be disconnected, and the storage battery system may continue to operate with only the other battery units.

After repair of the disconnected battery unit is completed, when reconnecting the battery unit in parallel with the battery unit in operation, if there is a large voltage difference between the battery units, an excessive inrush current may occur immediately after the contactor is turned on. occur. A fuse is installed in the battery panel to protect against overcurrent, and it must be avoided that the fuse blows unintentionally due to overcurrent. In addition, when an excessive charge/discharge current flows through the storage battery, there is concern that it may cause deterioration of the storage battery or damage the storage battery. Therefore, in order to suppress the occurrence of this inrush current, when a voltage difference exceeding a certain level occurs between battery panels, protection is provided so that the contactor of the battery panel is not turned on, and the voltage difference between the battery units is suppressed. It is necessary to turn on the contactor again after the problem is resolved. There is a risk that it will take time to adjust the difference.

The present invention has been made in view of the above. It is an object of the present invention to provide a monitoring control device, a storage battery system, and a method capable of automatically reconnecting a failed battery unit to a power storage system for recovery.

A monitoring control device according to an embodiment is a monitoring control device that performs monitoring control of a plurality of battery unit groups each composed of a plurality of battery units and a PCS that charges and discharges the battery units. When a new battery unit is connected in parallel to a battery unit that is normally electrically connected to the PCS, the difference between the voltage of the new battery unit and the voltages of all the normally connected battery units Based on the voltage difference and the charge/discharge command value, a first corrected charge/discharge command value is generated so as to reduce the voltage difference for the PCS to which the new battery unit is to be connected, and the charge/discharge command value and the first correction are generated. A correction unit that generates and outputs a second corrected charge/discharge command value for the PCS other than the PCS to which the new battery unit is to be connected based on the charge/discharge command value, the voltage of the new battery unit, and the normal a voltage judgment unit for judging whether or not the voltage difference between the voltages of all the battery units connected to is within a predetermined allowable voltage difference; a connection processing unit that electrically connects a new battery unit via a contactor when the voltage difference is within the voltage difference.

FIG. 1 is a schematic configuration block diagram of the storage battery system of the first embodiment. FIG. 2 is an explanatory diagram of a case where one battery unit has failed and stopped. FIG. 3 is a processing flow chart at the time of failure recovery. FIG. 4 is an explanatory diagram of a screen configuration example for automatically restoring a failed battery unit. FIG. 5 is an explanatory diagram of a case where one battery unit has failed and stopped in the second embodiment. FIG. 6 is a flowchart relating to power distribution control for early and automatic recovery of a stopped battery unit when multiple PCS are controlled simultaneously. FIG. 7 is an explanatory diagram of the third embodiment. FIG. 8 is a flowchart relating to power distribution control according to the third embodiment.

Prior to describing the embodiments, the technical background will be described.
In a storage battery system for a power system, a plurality of battery units (battery panels) are connected in parallel to form a large-capacity battery. This battery panel monitors and controls the storage battery with a control unit called BMU (Battery Management Unit), and when this BMU detects an abnormality (such as an abnormality in the storage battery), the corresponding battery panel is immediately stopped, Open (disconnect) the contactor.

At this time, continuing operation with only battery units in which no abnormality has occurred, reducing the number of battery units connected in parallel, and continuing charge/discharge is called degenerate operation.
After the failed battery unit is repaired, it is reconnected to the storage battery system that continues the degenerate operation, thereby restoring the entire system to a normal state.

However, if the disconnected battery panels are reconnected while there is a large voltage difference between the parallel-connected battery units, an excessive current will flow between the parallel-connected battery panels, causing damage to the storage battery and equipment. may lead to

Therefore, when restoring a failed battery panel, it was necessary to match the battery voltage of the battery unit operating normally with the battery voltage of the battery unit to be restored from the failure.
In the following description, a technique for simplifying the task of matching the battery voltage of a battery unit operating normally and the battery voltage of a battery unit to be restored from failure will be described.

(1) 1st Embodiment FIG. 1 : is a schematic block diagram of the storage battery system of 1st Embodiment.
The storage battery system 10 can be broadly divided into a storage battery device 11 that stores electric power, and a power conversion device (PCS: Power Conditioning System) 12.

The storage battery device 11 is roughly divided into a plurality of battery boards 21-1 to 21-N (N is a natural number) and a battery terminal board 22 to which the battery boards 21-1 to 21-N are connected. .
The battery boards 21-1 to 21-N include a plurality of battery units 23-1 to 23-M (M is a natural number) connected in parallel, a gateway device 24, and a BMU (Battery Management Unit), which will be described later. device) and a CMU (Cell Monitoring Unit) and a power supply device 25 that supplies power for operation.

Here, the configuration of the battery unit will be described.
Each of the battery units 23-1 to 23-M is supplied with an output power source via a high potential side power supply line (high potential side power supply line) LH and a low potential side power supply line (low potential side power supply line) LL. It is connected to lines (output power line; bus line) LHO and LLO, and supplies power to the power conversion device 12, which is the main circuit.

Since the battery units 23-1 to 23-M have the same configuration, the battery unit 23-1 will be described as an example.
The battery unit 23-1 can be broadly divided into a plurality of (24 in FIG. 1) cell modules 31-1 to 31-24 and a plurality of (24 in FIG. 1) cell modules 31-1 to 31-24 provided respectively. 1, 24 CMUs 32-1 to 32-24, a service disconnect 33 provided between the cell modules 31-12 and 31-13, a current sensor 34, a contactor 35, A plurality of cell modules 31-1 to 31-24, service disconnect 33, current sensor 34 and contactor 35 are connected in series.

Here, the cell modules 31-1 to 31-24 constitute an assembled battery by connecting a plurality of battery cells in series and parallel. A plurality of cell modules 31-1 to 31-24 connected in series form an assembled battery group.
Furthermore, the battery unit 23-1 has a BMU 36, and the communication lines of the CMUs 32-1 to 32-24 and the output line of the current sensor 34 are connected to the BMU 36.

Under the control of the gateway device 24, the BMU 36 controls the entire battery unit 23-1, and the result of communication with each CMU 32-1 to 32-24 (voltage data and temperature data described later) and the detection result of the current sensor 34 Based on this, the opening/closing control of the contactor 35 is performed.

Next, the configuration of the battery terminal board will be described.
The battery terminal board 22 includes a plurality of board contactors 41-1 to 41-N provided corresponding to the battery boards 21-1 to 21-N, and a supervisory control configured as a microcomputer that controls the entire storage battery device 11. a device 42;

Between the power conversion device 12 and the power conversion device 12, the monitoring control device 42 includes a control power supply line 51 supplied via a UPS (Uninterruptible Power System) 12A of the power conversion device 12, and an Ethernet (registered trademark). A control communication line 52 for exchanging data is connected.
With the above configuration, the monitor control device 42 controls the battery units 23-1 to 23-M and the PCS12.

The storage battery system 10 is configured by combining battery cells and battery modules in multiple series and multiple parallel. Each of the battery units 23-1 to 23-M is provided with a contactor 35. When the storage battery system 10 is started, these contactors 35 are sequentially turned on (closed) to connect to the main circuit, thereby charging and discharging the storage battery. becomes possible.

In this case, if there is a difference in the amount of charge between the battery units 23-1 to 23-M and a large difference in voltage between the battery units 23-1 to 23-M, immediately after the contactor 35 is turned on. An excessive inrush current (cross current) is generated in the main circuit.
For example, assuming that there is a voltage difference ΔV between two battery panels that can be connected in parallel, the rush current I that flows when the contactor is turned on can be obtained from the following relational expression.

Here, R is the battery unit 23-X (X=1 to M), the internal resistance per unit (the sum of the internal resistances of the storage battery, wiring, etc.).
In addition, the storage battery system 10 is provided with a fuse (not shown) for overcurrent protection, and if an overcurrent flows in the main circuit, the fuse may blow unintentionally.

Furthermore, when an overcurrent flows through the storage battery, it becomes a factor of deterioration of the storage battery, and there is a risk of damaging the storage battery.
Therefore, in order to prevent the occurrence of this rush current, it is necessary to protect the contactor 35 of the battery unit 23 from being turned on when a voltage difference exceeding a certain level occurs between the battery units 23 connected in parallel. .

FIG. 2 is an explanatory diagram of a case where one battery unit has failed and stopped.
For ease of understanding, FIG. 2 shows the case where the battery units 23-1 to 23-5 are connected.
In the following description, when it is necessary to identify the contactor 35 for each of the battery units 23-1 to 23-5, the contactors 35-1 to 23-5 are used.

More specifically, as shown in FIG. 2, in the storage battery system 10, the battery units 23-1 to 23-5 are connected in parallel, and the battery unit 23-2 has failed. there is

The battery units 23-1, 23-3 to 23-5 that are operating normally continue the charge/discharge control by the PCS12.
Therefore, the state of charge (SOC) is different from that of the battery unit 23-2 that has failed.

Here, when the battery unit 23-2 that has recovered from failure due to replacement or repair of the battery unit is reinserted, the battery units 23-1, 23-3 to 23 in which the storage battery monitoring control device 42 is operating normally It is necessary to adjust the battery voltage of -5 to the battery voltage of the battery unit 23-2 that has recovered from the failure, and then turn on (close) the contactor 35-2.

FIG. 3 is a processing flow chart at the time of failure recovery.
FIG. 3 is a flowchart of processing that can be performed when there are n (one or more) battery units to be restored. That is, as in the above example, if only the battery unit 23-2 among the battery units 23-1 to 23-5 has failed, the number of battery units to be restored is one, and n=1. becomes.
The battery terminal board 22 includes a voltage detector (VD: Voltage Detector) (not shown) for measuring the voltage of a main circuit in which a plurality of battery units 23-1 to 23-5 are connected in parallel.
In this case, after replacing or repairing the failed battery unit, the maintenance personnel designates the battery unit to be restored (battery unit 23-2 in this example) to be reconnected to the monitoring control device 42, and restores the battery unit. Start processing.
As a result, the monitoring control device 42 first sets the parameter i=1 for identifying the n battery units 23-X to be restored as an initial setting (step S11).
Next, the power of the BMU 36 of the battery unit 23-X to be restored corresponding to the parameter i is turned on to put it in a standby state (step S12).

Subsequently, the monitoring control device 42 sets the voltage tolerance between the voltage of the battery unit 23-X to be restored corresponding to the parameter i and the main circuit voltage at the time (step S13). This is because the larger the voltage difference between the battery panels, the larger the inrush current (cross current) flowing in the main circuit, so that the current value at the time of return connection should be less than or equal to the allowable current value.

Then, the monitoring control device 42 transmits an operation command to the BMU 36 of the battery unit 23-X to be restored corresponding to the parameter i (step S14).
Furthermore, the monitoring control device 42 starts a monitoring timer for managing the period of monitoring processing of the main circuit voltage for each battery unit to be restored (step S15).
Subsequently, the difference between the voltage of the battery unit 23-X to be restored corresponding to the parameter i and the main circuit voltage is calculated (step S16).

Subsequently, the monitoring control device 42 determines whether or not the voltage difference calculated in step S16 is equal to or less than the voltage tolerance set in step S13 (step S17).
That is, it is determined whether or not the battery unit 23-X to be restored corresponding to the parameter i can be connected to the main circuit.

In the determination of step S17, if the voltage difference calculated in step S16 is equal to or less than the voltage tolerance set in step S13 (step S16; Yes), the recovery target battery unit 23-X corresponding to the parameter i is Since it is determined that the battery unit 23-X can be connected to the main circuit, the contactor of the battery unit 23-X is turned on (step S19), and the process proceeds to step S21.

In the judgment of step S17, if the voltage difference calculated in step S16 exceeds the voltage tolerance set in step S13 (step S16; No), at that time, the battery to be restored corresponding to the parameter i Since the unit 23-X cannot be connected to the main circuit, the supervisory control device 42 determines whether or not the timeout period has elapsed (step S18).

If it is determined in step S18 that the timeout period has not elapsed yet (step S18; No), the monitoring control device 42 shifts the processing to step S16 again, and repeats the above-described processing.

In the judgment of step S18, if the timeout period has passed (step S18; Yes), at that time, the battery unit 23-X to be restored corresponding to the parameter i cannot be connected to the main circuit. The device 42 stops the power supply of the BMU 36 of the battery unit 23-X to be restored corresponding to the parameter i (step S20).

Subsequently, the monitoring control device 42 stops the monitoring timer (step S21) and sets the parameter i=i+1 (step S22).
Next, the monitoring control device 42 determines whether or not the parameter i has exceeded the number n of battery units 23-X to be restored, that is, whether or not the processing for all the battery units 23-X to be restored has been completed. (Step S23).
If it is determined in step S23 that the parameter i has not yet exceeded the number n of battery units 23-X to be restored (step S23; No), the process for all battery units 23-X to be restored is finished. Therefore, the monitoring control device 42 shifts the processing to step S12 again, and repeats the above-described processing until the processing for all battery units 23-X to be restored is completed.
In the judgment of step S23, if the parameter i exceeds the number n of battery units 23-X to be restored (step S23; Since the processing has been completed, the processing ends.

As described above, the monitoring control device 42 monitors the voltage difference between the main circuit voltage and the voltage of the battery unit 23-X to be restored, and when the voltage difference falls within the allowable range, the battery unit 23 to be restored By automatically closing the contactor 25 corresponding to -X, recovery processing can be performed safely and efficiently.

FIG. 4 is an explanatory diagram of a screen configuration example for automatically restoring a failed battery unit.
This screen is assumed to be a screen of a maintenance tool or the like.
FIG. 4 shows an example in which two BMUs 36 with BMU numbers=“01” and “15” for specifying the BMUs 36 have stopped due to the occurrence of a failure.
After repairing the two battery units that have failed and stopped, the maintenance personnel checks (clicks) the selection boxes corresponding to the two BMUs 36 with BMU numbers=“01” and “15” as restoration targets on this screen G1. In the selected state, the automatic recovery operation start button BST is clicked to start the automatic recovery operation.
As a result, the supervisory control device 42 first turns on the power of the BMU 36 with the BMU number=“01” to put it in a standby state.
In this state, other normally operating battery units (battery units corresponding to BMUs other than BMU numbers=“01” and “15”) continue charging and discharging.
Therefore, in the example of FIG. 4, the unit voltage (battery voltage) of the other battery units operating normally is 610V.

On the other hand, the unit voltage of the battery unit having the BMU 36 corresponding to the BMU number=“01” is as low as 520 V, exceeding the allowable voltage difference (for example, 10 V), and cannot be reconnected. be.

However, the storage battery system 10 continues charge/discharge control by degenerate operation, and the main circuit voltage increases during charging, and conversely decreases during discharging.
Therefore, the monitoring control device 42 constantly monitors the difference between the unit voltage of the battery unit having the BMU 36 corresponding to the BMU number=“01” to be restored and the main circuit voltage, and the voltage difference is within the tolerance. When entering, the contactor 35 of the battery unit equipped with the BMU 36 corresponding to the BMU number=“01” is turned on to reconnect.
After that, the monitoring control device 42 will perform the same recovery processing for the battery unit having the BMU 36 corresponding to the BMU number=“15”.

As described above, according to the first embodiment, when recovering from a faulty state, maintenance personnel only need to issue a recovery instruction after replacing or repairing the faulty battery unit. , the battery unit corresponding to the failure can be automatically reconnected to the power storage system for recovery.

[2] Second Embodiment In the above-described first embodiment, the configuration is such that restoration is performed when the voltage difference between the main circuit voltage and the battery unit to be restored falls within the tolerance. If the voltage difference of the battery unit to be restored does not fall within the allowable range, the contactor of the battery unit to be restored cannot be turned on, and the restoration process may take time.
Therefore, in the second embodiment, in the configuration in which the monitoring control device 42 simultaneously controls a plurality of PCS, the system rated output (the total value of the PCS rated output) has a margin for the charge/discharge command value from the host device. In such a case, an embodiment will be described in which the power distribution is distributed within the range of the surplus power to shorten the processing time of the automatic restoration process.

FIG. 5 is an explanatory diagram of a case where one battery unit has failed and stopped in the second embodiment.
In the first embodiment, the supervisory control device 42 controls only one PCS 42, but in the second embodiment, the supervisory control device 42A controls a plurality of PCS 12-1 to 12-4. are taking

Each PCS 12-1 to 12-4 further includes corresponding battery units 23-1-1 to 23-5-1, 23-1-2 to 23-5-2, 23-1-3 to 23-5-3. , 23-1-4 to 23-5-4.

In this case, the supervisory control device 42A controls the plurality of PCSs 12-1 to 12-4 via Ethernet or the like, and a higher-level device (EMS: Energy Management System or SCADA: Supervisory Control System) positioned above the supervisory control device 42 And Data Acquisition, etc.), and distributes the charge/discharge command values to each of the PCS 12-1 to 12-4.

That is, the monitoring control device 42A may evenly distribute the charge/discharge command to each PCS 12-1 to 12-4, or may distribute power to each PCS 12-1 to 12-4 in consideration of the SOC. However, the latter will be explained in the third embodiment, and in the second embodiment, the case of equal distribution will be explained.

By the way, in the configuration in which the supervisory control device 42A simultaneously controls a plurality of PCS 12-1 to 12-4, the system rated output (the total value of the PCS rated output) has a surplus with respect to the charge/discharge command value from the host device. In this case, the power distribution can be distributed within the range of the surplus capacity.
Therefore, in the second embodiment, the time required for recovery processing is shortened by controlling the charge/discharge commands to each of the PCS 12-1 to 12-4.

More specifically, as shown in FIG. 5, the battery unit 23-2-1 corresponding to the PCS 12-1 has failed, and the other normal battery units 23-1-1 and 23-3-1 ~ 23-5-1, 23-1-2 ~ 23-5-2, 23-1-3 ~ 23-5-3, 23-1-4 ~ 23-5-4 continue degenerate operation shall be

In this case, when the supervisory control device 42A receives a charge/discharge command from the host device, it distributes the charge/discharge command to each of the PCS 12-1 to 12-4.
By the way, in order to perform recovery processing for the battery unit 23-2-1 that has recovered from the failure, the normally operating battery units 23-1-1, 23-3-1 to 23-5 corresponding to the PCS 12-1 must -1 must match the battery voltage of the battery unit 23-2-1 disconnected due to failure.

In this case, the battery unit 23-2-1 in failure stop has a smaller amount of charge than the other normal battery units 23-1-1, 23-3-1 to 23-5-1. , the battery voltage is low.

On the other hand, battery unit groups (23-1-2 to 23-5-2, 23-1-3 to 23-5-3, 23-1-4 to 23 -5-4) may be equal to the charge amount (or battery voltage) of the battery group (23-3-1 to 23-5-1) of the battery unit connected to PCS 12-1, It may be different.

Here, between the battery units connected in parallel to each of the PCS 12-1 to 12-4 and operating normally (for example, the charging of the batteries 23-1-3 to 23-5-3 connected to the PCS 12-3) The amounts are roughly equal and the battery voltages are also equal.

Therefore, the monitoring control device 42A distributes power by allocating the charge/discharge command from the host device to each charge/discharge command value of the PCS 12-1 to PCS 12-4.

That is, the charge/discharge command value to the PCS 12-1 to which the battery unit 23-2 to be restored is connected is controlled, and the other normally operating battery units 23-1-1, 23-3-1 to 23 - Allocate the charge/discharge amount of 5-1 so as to match the charge amount of the battery unit 23-2-1 to be restored. At this time, by distributing the difference to the other PCS 12-2 to 12-4, the battery unit that has been disconnected is restored while continuing the charge/discharge control by the host device.

More specifically, the battery voltages of the battery units 23-1-1, 23-3-1 to 23-5-1 connected in parallel to the PCS 12-1 and the battery unit 23-2- 1, it is necessary to discharge the battery units 23-1-1, 23-3-1 to 23-5-1 in order to keep the difference in battery voltage within the restorable allowable voltage difference.

Therefore, in the monitoring control device 42A, the PCS 12-1 discharges the battery units 23-1-1, 23-3-1 to 23-5-1, and the battery unit 23-2-1 in the failure stop state is discharged. In order to keep the voltage difference within the allowable voltage difference, priority is given to the discharge operation of the PCS 12-1, and the charge/discharge amounts of the other PCS 12-2 to PCS 12-4 are controlled.

For example, when discharging as a whole, the monitoring control device 42A preferentially discharges the battery units 23-1-1, 23-3-1 to 23-5-1 connected to the PCS 12-1. let it happen

In addition, when the monitoring control device 42A performs charging as a whole, the monitoring control device 42A, 23-1-2 to 23-5-2 and 23-1-3 to 23- connected to the PCS12-2 to PCS12-4, respectively. 5-3, 23-1-4 to 23-5-4 are preferentially charged, and the battery units 23-1-1, 23-3-1 to 23-5- connected to the PCS 12-1 1 charging should be avoided as much as possible.

FIG. 6 is a flowchart relating to power distribution control according to the second embodiment.
In the process of FIG. 6, when controlling a plurality of PCS at the same time, power distribution control is performed for early and automatic recovery of the stopped battery unit.
Here, description will be made with reference to FIG. 5 again.
First, the monitoring control device 42A defines the number of connected PCSs Npcs=4 and the upper command value Pcmd [kW] (for example, discharging direction: positive value, charging direction: negative value), and sets them as initial values. (Step S31).

Subsequently, the monitoring control device 42A determines whether or not the storage battery system 10 is in a degenerate operation in which there is a battery unit in a failure stop state (step S32).

In the judgment of step S32, if the storage battery system 10 is not in the degenerate operation where there is a battery unit in the failure stop state (step S32; No), the monitoring control device 42A instructs each of the PCS 12-1 to 12-4 to The upper command value Pcmd [kW] is divided by the number of connected PCSs Npcs, and is evenly distributed to the four PCSs (step S39).

In the judgment of step S32, if the storage battery system is in a degenerate operation (if there is one or more battery units that are in failure stoppage and automatic recovery processing has started), the monitoring control device 42A (In the case of the above example, the battery unit 23-2-1) unit voltage Vrep and the unit voltages of the other normally operating battery units 23-1-1, 23-3-1 to 23-5-1 Vnorm is compared, and if the voltage difference is within the allowable difference, the 35-2-1 corresponding to the disconnected battery unit 23-2-1 is turned on to restore.

If the voltage difference exceeds the tolerance, the supervisory control device 42A
Vrep<Vnorm
(step S33).
In the judgment of step S33, if Vrep<Vnorm (step S33; Yes), other battery units 23-1-1, 23-3-1 to 23-5-1 that are normally operating are discharged. Therefore, the monitoring control device 42A determines a correction command value Prep (discharge command) for matching the voltage difference between the battery units (step S34).

In the judgment of step S33, if Vrep>Vnorm (step S33; No), other battery units 23-1-1, 23-3-1 to 23-5-1 that are normally operating are not charged. Therefore, the monitoring control device 42A determines a correction command value Prep (charging command) for matching the voltage difference between the battery units (step S35).

In this case, the correction command value Prep is determined within the rated output range of the PCS 12-1 to 12-4, and is preset to ±50 kW (+: discharge command, -: charge command), for example.

Next, the monitoring control device 42A determines whether or not the command content (charge or discharge) of the upper command value Pcmd and the command content (charge or discharge) of the correction command value Prep are inconsistent (step S36).

If the command content of the upper command value Pcmd and the command content of the correction command value Prep do not match in the judgment of step S36 (step S36; Yes), that is, if one is charging and the other is discharging , the supervisory control device 42A sets the command value to the PCS (PCS 12-1 in the above example) to which the battery unit to be restored is connected as the correction command value Prep, and sets the charge/discharge command value from the host device to other PCS (PCS12-2 to PCS12-4 in the above example). At this time, in order to cancel the correction command value Prep, the command value opposite to the correction command value is added to the upper command value (P'cmd=Pcmd−Prep) to determine the charge/discharge command value for each PCS. , to each PCS.

Specifically, the supervisory control device 42A determines that the post-correction upper command value P′cmd is the total value Pmax of the chargeable and dischargeable outputs of Npcs−1 PCS (usually the total value of the rated output of the PCS, 500 kW × 3 units = 1500 kW, etc.), that is,
Pmax≧Pcmd−Prep
(step S37).

In the determination of step S37, if Pcmd-Prep>Pmax (step S37; No), the correction command value cannot be canceled, so the monitoring control device 42A instructs each of the PCS 12-1 to 12-4 to The upper command value Pcmd [kW] is divided by the number of connected PCSs Npcs, and is evenly distributed to the four PCSs (step S39).

In the judgment of step S37, if Pmax≧Pcmd−Prep (step S37; Yes), the charge/discharge command for the PCS 12-1 to which the battery unit to be restored is connected is set to the correction command value Prep, and the other PCS The charge/discharge command is a value obtained by evenly distributing the corrected upper command value P'cmd in units of (Npcs-1) (three PCS 12-2 to 12-4 in the above example) (step S38).

As described above, according to the second embodiment, while the output of the entire storage battery system 10 is adjusted to the upper command value, the stopped battery unit (in the case of the above example, the battery unit 23-2-1 ) can be given, and the time required for automatic restoration of the disconnected battery unit can be shortened compared to the first embodiment.

By the way, when the contactor of the disconnected battery unit (the contactor 35-2-1 of the battery unit 23-2-1 in the above example) is turned on, the voltage of the battery unit in operation is CCV (Closed Circuit Voltage: The voltage of the disconnected battery unit indicates OCV (Open Circuit Voltage).

Therefore, when the contactor is turned on, the voltage of the disconnected battery unit becomes the closed circuit voltage CCV obtained by adding/subtracting the battery internal resistance Rb×the charging/discharging current I to/from OCV. If there is a difference between this CCV and the CCV of another battery unit (battery unit in operation), a cross current will occur according to the voltage difference. Therefore, when the voltage difference between the operating battery unit and the disconnected battery unit gradually decreases, the correction command value Prep is gradually decreased to prevent an excessive cross current when the contactor 35 is turned on. It is also possible to prevent the occurrence.

[3] Third Embodiment In the above-described second embodiment, the monitoring control device 42 evenly distributes the charge/discharge command value from the host device to a plurality of PCS, but instead performs automatic restoration processing. If the charge/discharge amount of the PCS (storage battery group) deviates from the other PCS, some PCS may reach the upper and lower limit voltages first, and charging/discharging may not be continued.
Therefore, in the third embodiment, electric power distribution is performed for the purpose of SOC adjustment, thereby adjusting the amount of charge between the PCSs while continuing the charge/discharge control of the storage battery system.
For example, the method described in Patent Document 2 can be cited as a configuration of power distribution for the purpose of SOC adjustment.

If this method is applied, the charge/discharge command value for each PCS is determined based on the charging needs characteristics, and only some battery units reach the upper and lower limit voltage (end of charge or end of discharge) of the storage battery and temporarily The effect of preventing the charging/discharging impossible state is expected.
A specific description will be given below.

FIG. 7 is an explanatory diagram of the third embodiment.
In the case where the state shown in FIG. 7 immediately after the disconnected battery unit 23-2 is automatically restored by the method of the second embodiment, the monitoring control device 42 continues to issue a discharge command from the host device. If the battery group of PCS 12-1 reaches the lower limit voltage (end of discharge) first, PCS 12-1 cannot continue discharging. .

Therefore, in the third embodiment, the power distribution method disclosed in Patent Document 2 is applied, and power distribution control is performed in consideration of charging needs characteristics.

Here, the charging needs characteristic is a characteristic value based on the deterioration rate characteristic for each value of the SOC and temperature of the storage battery. is desirable), and a negative value (discharge is desirable) when the deterioration rate is reduced by making the SOC lower than the current SOC.

FIG. 8 is a flowchart relating to power distribution control according to the third embodiment.
In FIG. 8, parts similar to those in FIG. 6 are denoted by the same reference numerals, and the detailed description thereof is incorporated.
The difference between the third embodiment and the second embodiment is that, in the power distribution control for each PCS, instead of equal distribution, power distribution control is performed in consideration of charging need characteristics.
Now, in the case of a storage battery that has the slowest deterioration rate at an SOC of 50% as a storage battery characteristic, it has a positive NOC (needs of charge) at a low SOC and a negative NOC at a high SOC. Become.
In such a storage battery system, when the monitoring control device 42 distributes the power of the charging command, the command value is distributed from the PCS with the highest NOC. Conversely, when distributing the electric power of the discharge command, the command value is distributed from the PCS with the lowest NOC.

A specific description will be given below.
Since the processing from step S31 to step S35 is the same as that of the second embodiment, the processing after step S36 will be described below.

When the processing of steps S33 to S35 is completed, the monitoring control device 42A determines whether or not the command content (charge or discharge) of the upper command value Pcmd and the command content (charge or discharge) of the correction command value Prep do not match. It judges (step S36).

If the command content of the upper command value Pcmd and the command content of the correction command value Prep do not match in the judgment of step S36 (step S36; Yes),
Pmax≧Pcmd−Prep
(step S37).

In the determination of step S37, if Pcmd-Prep>Pmax (step S37; No), the correction command value cannot be canceled, so the monitoring control device 42A controls the PCS 12-1 to 12-4. Power distribution control is performed in consideration of charging needs characteristics (step S42).

In the judgment of step S37, if Pmax≧Pcmd-Prep (step S37; Yes), the charge/discharge command for the PCS 12-1 to which the battery unit to be restored is connected is set to the correction command value Prep, and the other PCS 12- 2 to 12-4 charge/discharge commands perform power distribution control in consideration of charging needs characteristics (step S41).

That is, in the third embodiment, the PCS (PCS 12-1 in the above example) to which the battery board that is in the process of automatic recovery is connected is excluded from this distribution control target, and the other PCS (the above In the example, distribution control is performed only by PCS 12-2 to 12-4). After that, after the automatic restoration of the battery board is completed, the PCS (PCS 12-1 in the above example) to which the battery board is connected is returned to the distribution control based on the charging need characteristics.

As a result, in the example of FIG. 7, the charging needs of the PCS 12-1 are higher than those of the other PCS 12-2 to 12-4, making it difficult to allocate the discharge command to the PCS 12-1, and on the contrary, giving priority to the charging command. As a result, in addition to the effect of the second embodiment, the effect of keeping the SOC of the entire system appropriately even after the automatic restoration can be obtained.

[4] Modification of Embodiment The program executed by the monitoring and control apparatus of this embodiment is a file in an installable format or an executable format, and can be stored on an optical recording medium such as a DVD (Digital Versatile Disk), a USB memory, or an SSD. (Solid State Drive) and other computer-readable recording media such as semiconductor memory devices.

Alternatively, the program executed by the monitoring and control apparatus of this embodiment may be stored in a computer connected to a network such as the Internet, and may be provided by being downloaded via the network. Also, the program executed by the monitoring control device of this embodiment may be configured to be provided or distributed via a network such as the Internet.

Further, the program of the monitoring control device of the present embodiment may be configured so as to be pre-installed in a ROM or the like and provided.

While several embodiments of the invention have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and equivalents thereof.

10 storage battery system 11 storage battery device 12, 12-1 to 12-4 power conversion device (PCS)
21-1 to 21-N Battery board 23-1 to 23-M Battery unit 23-1-1 to 23-5-4 Battery unit 35, 35-1-1 to 35-5-2 Contactor

Claims (6)

A monitoring control device for monitoring and controlling a plurality of battery unit groups each configured by a plurality of battery units and a PCS for charging and discharging the battery units,
When a new battery unit is connected in parallel to a battery unit already electrically connected to any of the PCS in a normal manner, the voltage of the new battery unit and the voltage of the normally connected battery unit Based on the voltage difference from the voltages of all the battery units connected to the new battery unit and the charge/discharge command value, the first corrected charge/discharge command value is set so as to reduce the voltage difference for the PCS to be connected to the new battery unit. and generating a second corrected charge/discharge command value for a PCS other than the PCS to be connected to the new battery unit based on the charge/discharge command value and the first corrected charge/discharge command value; a correction unit that outputs;
a voltage determination unit that determines whether a voltage difference between the voltage of the new battery unit and the voltages of all the battery units that are normally connected is within a predetermined allowable voltage difference;
a connection processing unit that electrically connects the new battery unit via a contactor when the voltage difference is within a predetermined allowable voltage difference based on the determination of the voltage determination unit;
A supervisory control device with The correcting unit makes the sum of the charge/discharge amount corresponding to the first corrected charge/discharge command value and the charge/discharge amount corresponding to the second corrected charge/discharge command value equal to the charge/discharge amount of the charge/discharge command value. generating the second corrected charge/discharge command value so that
2. The supervisory control device according to claim 1 . The correction unit gradually decreases the first corrected charge/discharge command value when the voltage difference becomes small.
3. The supervisory control device according to claim 1 or 2 . The monitoring control device removes the PCS to which the new battery unit is connected from among the plurality of PCS until the voltage difference is within a predetermined allowable voltage difference based on the determination of the voltage determination unit. performing power distribution control for the PCS, taking into account charging needs characteristics;
4. The supervisory control device according to any one of claims 1 to 3 . a plurality of battery units;
a plurality of PCSs that charge and discharge a plurality of battery units that are different from each other;
When a new battery unit is connected in parallel to a battery unit already electrically connected to any of the PCS in a normal manner, the voltage of the new battery unit and the voltage of the normally connected battery unit Based on the voltage difference from the voltages of all the battery units connected to the new battery unit and the charge/discharge command value, the first corrected charge/discharge command value is set so as to reduce the voltage difference for the PCS to be connected to the new battery unit. and generates a second corrected charge command value for a PCS other than the PCS to be connected to the new battery unit based on the charge/discharge command value and the first corrected charge/discharge command value, and outputs and a voltage determination unit that determines whether or not the voltage difference between the voltage of the new battery unit and the voltages of all the battery units that are normally connected is within a predetermined allowable voltage difference. and a connection processing unit that electrically connects the new battery unit via a contactor when the voltage difference is within a predetermined allowable voltage difference based on the determination of the voltage determination unit. , a monitoring control device for monitoring and controlling a plurality of battery unit groups respectively composed of a plurality of battery units and a PCS for charging and discharging the battery units;
A storage battery system with A method that is executed by a monitoring control device that performs monitoring and control of a plurality of battery unit groups each composed of a plurality of battery units and a PCS that charges and discharges the battery units,
When a new battery unit is connected in parallel to a battery unit already electrically connected to any of the PCS in a normal manner, the voltage of the new battery unit and the voltage of the normally connected battery unit Based on the voltage difference from the voltages of all the battery units connected to the new battery unit and the charge/discharge command value, the first corrected charge/discharge command value is set so as to reduce the voltage difference for the PCS to be connected to the new battery unit. and generates a second corrected charge command value for a PCS other than the PCS to be connected to the new battery unit based on the charge/discharge command value and the first corrected charge/discharge command value, and outputs the process of
determining whether the voltage difference between the voltage of the new battery unit and the voltages of all the normally connected battery units is within a predetermined allowable voltage difference;
a step of electrically connecting the new battery unit via a contactor when the voltage difference is within a predetermined allowable voltage difference based on the determination;
A method with

Images