JP6071539B2 - Power storage system and control method - Google Patents

Description

The present invention relates to a power storage system that controls power to be charged / discharged in an electric storage device, and a control method for the power storage system .

  In the power storage system, a power storage device such as a lithium ion battery is used. Electric power for charging and discharging the power storage device is performed by controlling a power converter provided at the output terminal of the power storage device. The power converter receives an input of a power command value indicating the required power, and outputs power based on the power command value.

  At this time, there is an error of about 1% or less between the power indicated by the power command value input to the power converter and the power actually output by the power converter, and they do not match. This is due to an error of a sensor provided in the power converter. However, since the error is about 1% or less, when the power converter is used in an electric motor control system that receives power supply from the power system, the error is not a problem in practice.

  On the other hand, when the power converter is provided in the power storage system, the error is accumulated because the power converter operates for a long time, and the value calculated as the amount of power charged in the power storage device and the power storage device There may be a large error between the actual amount of power being charged. For example, when the output error of the power converter is 0.2 kilowatts per hour, if the power storage system including the power converter is operated for 8 hours per day for 5 days, the power amount error of 8 kilowatt hours is increased. Arise. In one example of a household storage battery system, it is understood that the error is not small in view of the capacity of the secondary battery being 5 kWh.

  Patent Document 1 discloses a technique for correcting a difference between a power command value input to a power converter and an actual power value. According to Patent Document 1, the input / output power to the power storage device is actually measured during operation of the system to obtain a difference from the power command value, and the power command is corrected based on the difference. At this time, considering the transmission delay and computation delay during signal transmission, and the fact that the actual power does not change stepwise due to the time constant of the power circuit even if the power command changes stepwise, the power command The information is dulled once, and the difference between the dull power command information and the actual input / output power is taken.

JP 2011-097693 A

However, the method of dulling the power command information needs to be adjusted according to the transmission delay or calculation delay in the system, the time constant of the power circuit, etc. Even if the method described in Patent Document 1 is used, the system There is a problem that adjustment work is required every time. In addition, when using the method described in Patent Document 1, a circuit for smoothing power deviation (difference between dull power command information and input / output power) and compensating for delay (dulling power command information) There is a problem that the apparatus becomes complicated.
An object of the present invention is to provide a power storage system and a control method for setting the output power of a power converter to an appropriate value with a simple configuration.

The present invention has been made to solve the above problems, an electric storage device, provided at an output terminal of said power storage device, a power converter for charging and discharging the power indicated by the power command value to the electric storage device, An input unit that receives an input of a power command value indicating power to be output to the power converter, and the power converter outputs when the power indicated by the power command value and the power command value are input to the power converter. A storage unit that stores a data table or a function indicating a relationship with the power to be transmitted, and a power indicated by a power command value received by the input unit based on the data table or the function stored in the storage unit. to output the vessel, and a correcting unit for correcting the power command value by the input unit accepts the correction unit, the charging rate of the storage device, and said power storage device Scan is a power storage system and determining whether or not to correct the power command value according to whether is discharging or being charged.

  Further, the present invention includes a power detector that detects power output from the power converter, and the correction unit receives a power command value received by the input unit based on past power detected by the power detector. It is characterized by correcting.

Further, the present invention is pre-Symbol power detector, characterized in that it comprises an updating unit for updating the data table or the function the storage unit stores based on the power detected.

  In the present invention, the correction unit subtracts the power indicated by the power command value from the power output by the power converter when the power command value received by the input unit is input to the power converter. A value subtracted from the power indicated by the power command value is used as a corrected power command value.

  Further, in the present invention, the correction unit converts the power command value input to the power converter into a corrected power when the power converter outputs the power indicated by the power command value received by the input unit. It is a command value.

  The present invention further includes a temperature detector that detects the temperature of the power converter, and the correction unit corrects the power command value received by the input unit based on the temperature detected by the temperature detector. It is characterized by that.

  In the present invention, the correction unit determines whether to correct the power command value according to a charging rate of the power storage device.

Further, the present invention includes a storage device, provided at an output end of the electric storage device, the power indicated by the power command value A control method of a power storage system and a power converter for charging and discharging to the energy storage device, Receiving the input of a power command value indicating power to be output to the power converter, the charging rate of the power storage device, and the power command value depending on whether the power storage device is being charged or discharged When determining whether or not to correct the power, and when correcting the power command value, the power indicated by the power command value and the power command value stored in the storage unit are input to the power converter. The power converter outputs the power indicated by the power command value that has received the input based on a data table or a function indicating the relationship with the power output by the power converter In order, characterized in that it comprises the steps of correcting the power command value received the input.

  According to the present invention, the power command value is corrected based on the relationship between the power indicated by the power command value and the power output by the power converter when the power command value is input to the power converter. Thereby, it is possible to prevent an error from being accumulated in the charge / discharge power of the electricity storage device. Further, according to the present invention, the power control device does not need to smooth the power deviation or compensate for the delay, and thus can correct the power command value with a simple configuration.

It is a schematic block diagram which shows the structure of the electric power storage system which has an electric power control apparatus by the 1st Embodiment of this invention. It is a figure which shows the relationship between the electric power command value before correction | amendment which a memory | storage part memorize | stores, and the electric power command value after correction | amendment. It is a flowchart which shows operation | movement of the power control apparatus by the 1st Embodiment of this invention. It is a figure which shows the 1st production | generation method of the relationship between the electric power command value before correction | amendment, and the electric power command value after correction | amendment. It is a figure which shows the 2nd production | generation method of the relationship between the electric power command value before correction | amendment, and the electric power command value after correction | amendment. It is a schematic block diagram which shows the structure of the electric power storage system which has an electric power control apparatus by the 2nd Embodiment of this invention. It is a flowchart which shows operation | movement of the power control apparatus by the 2nd Embodiment of this invention. It is a schematic block diagram which shows the structure of the electric power storage system which has the electric power control apparatus by the 3rd Embodiment of this invention. It is a schematic block diagram which shows the structure of the electric power storage system which has the electric power control apparatus by the 4th Embodiment of this invention.

<< First Embodiment >>
Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic block diagram showing a configuration of a power storage system 1 having a power control device 20 according to the first embodiment of the present invention.
The power storage system 1 includes a power storage device 10 such as a lithium ion battery, a power control device 20 that controls power to be charged and discharged to the power storage device 10, and a power system 30 that outputs power of the power storage device 10.

The power control device 20 includes a power converter 21, an input unit 22, a storage unit 23, and a correction unit 24.
The power converter 21 receives an input of a power command value, and charges / discharges the power indicated by the power command value to / from the power storage device 10. However, the power converter 21 has an error between the value of the power command value and the output power. The power converter 21 is provided at the output end of the electricity storage device 10.
The input unit 22 receives an input of a power command value from the outside.
The storage unit 23 stores the relationship between the power command value before correction and the power command value after correction as information indicating the relationship between the power command value and the output power of the power converter 21.
The correction unit 24 corrects the power command value received by the input unit 22 based on the information stored in the storage unit 23.

FIG. 2 is a diagram illustrating the relationship between the power command value before correction stored in the storage unit 23 and the power command value after correction.
As illustrated in FIG. 2, the storage unit 23 stores the power command value before correction and the corrected power command value for causing the power converter 21 to output the power indicated by the power command value in association with each other. The storage unit 23 may store the relationship as a two-dimensional data table in which the power command value before correction and the power command value after correction are associated with each other, or the power command value before correction and the correction. You may memorize | store as a function which shows the relationship with subsequent electric power command value. When there is no error between the power indicated by the power command value input to the power converter 21 and the power actually output by the power converter 21, the power command value is the same before and after correction. Since there is an error between the power indicated by the power command value input to the power converter 21 and the power actually output by the power converter 21, the power command value is different before and after correction as shown in FIG. Takes a value.

Next, the operation of the power control apparatus 20 according to the present embodiment will be described.
FIG. 3 is a flowchart showing the operation of the power control apparatus 20 according to the first embodiment of the present invention.
The input unit 22 of the power control device 20 receives an input of a power command value from the outside (step S1). The power command value that the input unit 22 receives input is determined by the required power of the load connected to the power system 30 and the like.

  Next, the correction unit 24 specifies a corrected power command value associated with the power command value that the input unit 22 has received an input (step S2). When the storage unit 23 stores a two-dimensional data table in which the power command value before correction and the power command value after correction are associated with each other, the correction unit 24 uses the power command value received by the input unit 22. The two power command values before correction closest to are read out. Next, the correction unit 24 reads the corrected power command value associated with each of the two uncorrected power command values, and performs interpolation calculation of the corrected power command value, thereby correcting the power before correction. Specify the command value. On the other hand, when the storage unit 23 stores a function indicating the relationship between the power command value before correction and the power command value after correction, the correction unit 24 uses the power command value received by the input unit 22 as input. By substituting into this function, the corrected power command value is specified.

  And the correction | amendment part 24 inputs the electric power command value after correction | amendment specified by step S2 to the power converter 21 (step S3). Thereby, the power converter 21 outputs the electric power indicated by the power command value received by the input unit 22 by charging and discharging the power storage device 10 according to the corrected power command value. And the electric power control apparatus 20 performs the operation | movement of the said step S1-step S3 continuously until the electric power storage system 1 stops driving | operation.

  Here, a method for generating the relationship between the power command value before correction and the power command value after correction stored in the storage unit 23 will be described.

(First generation method)
FIG. 4 is a diagram illustrating a first generation method of the relationship between the power command value before correction and the power command value after correction.
First, a plurality of different power command values are input to the power converter 21, and the value of the power output from the power converter 21 when the power command value is input is specified (FIG. 4A). Next, for each power command value, a deviation amount of the output power with respect to the ideal output characteristic is calculated (FIG. 4B). Since the ideal output characteristic is such that the power command value and the output power match, the amount of deviation can be obtained by subtracting the power command value from the output power for each power command value. Then, the value obtained by weaving the deviation amount into the output power of the ideal output characteristic, that is, the value obtained by subtracting the deviation amount from the output power of the ideal output characteristic is the power command value after correction for the power command value. (FIG. 4C).

  Therefore, the input power command value and the calculated corrected power command value are associated with each other and recorded in the storage unit 23, thereby associating the storage unit 23 with the uncorrected power command value and the corrected power command value. A two-dimensional data table can be stored. Further, by performing linear approximation or curve fitting based on the input power command value and the calculated plurality of corrected power command values, the relationship between the power command value before correction and the corrected power command value is shown. A function may be calculated (FIG. 4D), and a data table may be generated based on the function. Further, the function may be recorded in the storage unit 23.

  In the example shown in FIG. 4, since the actual output characteristic is larger than the ideal output characteristic, the deviation amount becomes a positive number, and the corrected power command value is calculated based on the output power and the power from the output power of the ideal output characteristic. It is a value obtained by subtracting the command value difference (absolute value of the difference). On the other hand, when the actual output characteristic is smaller than the ideal output characteristic, the deviation amount becomes a negative number, and the corrected power command value adds the difference between the output power and the power command value to the output power of the ideal output characteristic. It becomes the value.

  When the relationship between the power command value before correction and the power command value after correction is recorded in the storage unit 23 using the first generation method, the power command value corrected by the correction unit 24 is input to the input unit 22. When the power command value received by is input to the power converter 21, a value obtained by subtracting the power indicated by the power command value from the power output from the power converter 21 is subtracted from the power indicated by the power command value.

(Second generation method)
FIG. 5 is a diagram illustrating a second generation method of the relationship between the power command value before correction and the power command value after correction.
First, a plurality of different power command values (FIG. 5A) are input to the power converter 21, and the value of power output by the power converter 21 when the power command value is input is specified (FIG. 5 ( B)). Next, a function indicating the actual output characteristics of the power converter 21 is calculated by performing linear approximation, curve fitting, or the like on the relationship between the input power command value and the output power (FIG. 5C). Next, for each input power command value, a power command value necessary for causing the power converter 21 to output the power indicated by the power command value is derived from a function indicating the actual output characteristics of the power converter 21. (FIG. 5D).

  Then, the input power command value and the power command value derived from the function are associated with each other and recorded in the storage unit 23, whereby the storage unit 23 associates the power command value before correction and the corrected power command value 2 A dimensional data table can be stored (FIG. 5E). Also, by performing linear approximation or curve fitting based on the input power command value and a plurality of corrected power command values derived from the function, the relationship between the power command value before correction and the power command value after correction May be calculated (FIG. 5F), and a data table may be generated based on the function. Further, the function may be recorded in the storage unit 23.

  When the relationship between the power command value before correction and the power command value after correction is recorded in the storage unit 23 using the second generation method, the power command value corrected by the correction unit 24 is input to the input unit 22. Is the value input to the power converter 21 when the power converter 21 outputs the power indicated by the received power command value.

  Thus, according to the present embodiment, the power control device 20 has a relationship between the power indicated by the power command value and the power output by the power converter 21 when the power command value is input to the power converter 21. Based on this, the power command value is corrected. Thereby, it is possible to prevent an error from being accumulated in the charge / discharge power of the electricity storage device 10.

  Further, according to the present embodiment, the power control device 20 includes the storage unit 23 without smoothing the output of the power converter 21 or compensating for delay, thereby correcting the power command value with a simple configuration. Can do.

<< Second Embodiment >>
Next, a second embodiment of the present invention will be described.
FIG. 6 is a schematic block diagram showing the configuration of the power storage system 101 having the power control device 120 according to the second embodiment of the present invention. Note that processing units that perform the same operations as those in the first embodiment will be described using the same reference numerals.
In addition to the configuration of the power control device 20 according to the first embodiment, the power control device 120 according to the second embodiment includes a power detector 25 that detects power output from the power converter 21 and a power detector 25. And an update unit 26 that updates information stored in the storage unit 23 based on the detected power. That is, the correction unit 24 corrects the power command value received by the input unit 22 based on the past power detected by the power detector 25.

FIG. 7 is a flowchart showing the operation of the power control apparatus 120 according to the second embodiment of the present invention. Note that steps that perform the same operations as in the first embodiment will be described using the same reference numerals.
The input unit 22 of the power control device 120 receives an input of a power command value from the outside (step S1). Next, the correction unit 24 specifies a corrected power command value associated with the power command value that the input unit 22 has received an input (step S2). And the correction | amendment part 24 inputs the electric power command value after correction | amendment specified by step S2 to the power converter 21 (step S3). Thereby, the power converter 21 outputs the electric power indicated by the power command value received by the input unit 22 by charging and discharging the power storage device 10 according to the corrected power command value.

  Next, the power detector 25 detects the power output from the power converter 21 (step S4). Next, the updating unit 26 subtracts the power command value input to the correction unit 24 from the power detected by the power detector 25 to obtain a subtraction value, and subtracts the subtraction from the power command value input to the correction unit 24. A value obtained by subtracting the value is calculated as a new corrected power command value (step S5). Then, the update unit 26 updates the corrected power command value associated with the power command value received by the input unit 22 in step S1 to the calculated new corrected power command value (step S6). .

  Thus, according to the present embodiment, the power control device 120 can correct the relationship between the corrected power command value and the corrected power command value during operation of the power storage system 101. Thereby, even when the characteristics change due to deterioration or temperature of the power converter 21, it is possible to cause the power converter 21 to output a desired amount of power.

<< Third Embodiment >>
Next, a third embodiment of the present invention will be described.
FIG. 8 is a schematic block diagram showing a configuration of a power storage system 201 having a power control device 220 according to the third embodiment of the present invention. Note that processing units that perform the same operations as those in the first embodiment will be described using the same reference numerals.
The power control apparatus 220 according to the third embodiment includes a temperature detector 27 that detects the temperature of the power converter 21 in addition to the configuration of the power control apparatus 20 according to the first embodiment.

  In addition, the storage unit 223 stores the power command value before correction and the power command value after correction in association with each temperature of the power converter 21. That is, the memory | storage part 223 memorize | stores the information produced | generated by the 1st method or the 2nd method mentioned above on the said temperature conditions for every temperature of the power converter 21. FIG.

  Further, the correction unit 224 reads information associated with the temperature detected by the temperature detector 27 from the storage unit 223, and corrects the power command value received by the input unit 22 based on the information.

  Thus, according to the present embodiment, the power control device 220 corrects the power command value that the input unit 22 has received the input based on the temperature of the power converter 21. Thereby, even when the characteristics change depending on the temperature of the power converter 21, it is possible to cause the power converter 21 to output a desired amount of power.

<< Fourth Embodiment >>
Next, a fourth embodiment of the present invention will be described.
FIG. 9 is a schematic block diagram showing a configuration of a power storage system 301 having a power control device 320 according to the fourth embodiment of the present invention. Note that processing units that perform the same operations as those in the first embodiment will be described using the same reference numerals.
The power control apparatus 320 according to the fourth embodiment includes a charge rate estimation unit 28 that detects the charge rate of the power storage device 10 in addition to the configuration of the power control apparatus 20 according to the first embodiment. As a method for estimating the charging rate, an open circuit voltage is estimated from the voltage of the power storage device 10 and a charging rate is calculated based on the open circuit voltage, or an integrated value of the current output from the power storage device 10 is calculated as a full value of the power storage device 10. For example, a method of calculating by dividing by the charge capacity may be used.

  Further, the correction unit 324 determines whether or not to correct the power command value received by the input unit 22 based on the charging rate estimated by the charging rate estimation unit 28. For example, the correction unit 324 does not perform correction when the charging rate of the power storage device 10 is 50% or more, and performs correction when the charging rate of the power storage device 10 is less than 50%.

  In addition, for example, the correction unit 324 may change a determination method for determining whether or not to correct depending on whether the power storage device 10 is being charged or discharged. Specifically, the correction unit 324 may use a determination method as described below. That is, when the power storage device 10 is being charged, the correction unit 324 performs correction when the charge rate of the power storage device 10 is 50% or more, and does not perform correction when the charge rate is less than 50%. On the other hand, the correction unit 324 performs correction when the charge rate of the power storage device 10 is less than 50 percent when the power storage device 10 is discharging, and does not perform correction when the charge rate is 50 percent or more.

  Thus, according to the present embodiment, the power control device 320 determines whether or not to correct the power command value according to the charging rate of the power storage device 10. Thereby, it is possible to prevent the accumulation of errors between the measured value and the calculated value of the power when the charging rate of the power storage device 10 is close to the lower limit or the upper limit.

Although several embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to that described above, and various designs can be made without departing from the scope of the present invention. It is possible to make changes.
For example, in the above-described embodiment, the case where the power storage system 1, 101, 201, 301 includes one power storage device 10 has been described. However, the present invention is not limited to this, and a plurality of power storage devices 10 are connected to the power converter 21. May be connected in parallel. In this case, the correction unit 324 of the power control device 320 according to the fourth embodiment may use the average charging rate of each power storage device 10 as a criterion for determining whether or not to correct the power command value. Alternatively, the maximum charging rate may be used. In addition, when the correction unit 324 changes the determination method for determining whether or not the power storage device 10 is being charged or discharged, when the power storage device 10 is being charged, The maximum charging rate of the device 10 may be used, and when the power storage device 10 is discharging, the minimum charging rate of the plurality of power storage devices 10 may be used.

  The power control apparatus 20 described above has a computer system inside. The operations of the correction units 24, 224, and 324 described above are stored in a computer-readable recording medium in the form of a program, and the above processing is performed by the computer reading and executing the program. Here, the computer-readable recording medium means a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like. Alternatively, the computer program may be distributed to the computer via a communication line, and the computer that has received the distribution may execute the program.

  The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

  DESCRIPTION OF SYMBOLS 1, 101, 201, 301 ... Power storage system 10 ... Power storage device 20, 120, 220, 320 ... Power control device 30 ... Power system 21 ... Power converter 22 ... Input part 23, 223 ... Storage part 24, 224, 324 ... correction unit 25 ... power detector 26 ... update unit 27 ... temperature detector 28 ... charge rate estimation unit

Claims (7)

An electricity storage device;
Provided at an output terminal of said power storage device, a power converter for charging and discharging the power indicated by the power command value to the electric storage device,
An input unit for receiving an input of a power command value indicating power to be output to the power converter;
A storage unit for storing a data table or a function indicating a relationship between the power indicated by the power command value and the power output by the power converter when the power command value is input to the power converter;
Based on the data table or the function stored in the storage unit, the power command value received by the input unit is corrected to cause the power converter to output the power indicated by the power command value received by the input unit. A correction unit to perform,
Equipped with a,
The correction unit determines whether to correct the power command value according to a charging rate of the power storage device and whether the power storage device is being charged or discharged.
A power storage system characterized by that. A power detector for detecting the power output by the power converter;
The power storage system according to claim 1, wherein the correction unit corrects a power command value received by the input unit based on past power detected by the power detector. The power storage system according to claim 2, further comprising an update unit that updates the data table or the function stored in the storage unit based on the power detected by the power detector. When the power command value received by the input unit is input to the power converter, the correction unit subtracts the power indicated by the power command value from the power output by the power converter. The power storage system according to any one of claims 1 to 3, wherein a value subtracted from the indicated power is used as a corrected power command value. When the power converter outputs the power indicated by the power command value received by the input unit, the correction unit uses the power command value input to the power converter as a corrected power command value. The power storage system according to any one of claims 1 to 3, characterized by: A temperature detector for detecting the temperature of the power converter;
Wherein the correction unit on the basis of the temperature by the temperature detector detects the power according to claims 1 to any one of claims 5, characterized in that to correct the power command value by the input unit accepts Storage system . A power storage system control method comprising: a power storage device; and a power converter that is provided at an output terminal of the power storage device and charges and discharges the power indicated by the power command value.
Receiving an input of a power command value indicating power to be output to the power converter;
Determining whether to correct the power command value according to a charging rate of the power storage device and whether the power storage device is being charged or discharged;
When correcting the power command value, the power indicated by the power command value stored in the storage unit and the power output by the power converter when the power command value is input to the power converter. Based on a data table or function indicating a relationship, correcting the power command value that has received the input to cause the power converter to output the power indicated by the power command value that has received the input;
A control method comprising:

Images