JP2015135550A - Control device of power control system and control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the profits of an owner of a power generator.SOLUTION: A power control system 1 includes a power generator 2 which uses natural energy to generate power, an electric storage device 3 connected between the power generator 2 and a power system 5, a power conversion device 4 which controls charge/discharge of the electric storage device 3, and a control device 10. The control device 10 determines whether the electric storage device 3 is in a state allowing charge/discharge or not and, in the case of the electric storage device being in the state allowing at least discharge, compares an electricity purchasing price and an electricity selling price with each other. If the electricity selling price is higher than the electricity purchasing price, the control device 10 outputs the selling electric power to the power system 5 as it is and selects a charge inhibition mode of charging/discharging the electric storage device 3 so that purchased electric power becomes zero, and generates a charge/discharge command on the basis of the selected mode and outputs the command to the power conversion device 4.

Description

  The present invention relates to a control device for a power control system and a control method therefor.

In recent years, a power control system that combines a power generation device that generates power using natural energy and a power storage device is known.
For example, Patent Document 1 discloses a function of converting electric power obtained by discharging a power generation device and a storage battery into alternating current and outputting the alternating current from the power system to direct current. There is disclosed a power control system that includes a power conversion device having a function of outputting power to the power system so as not to adversely affect the power system by controlling the purchased power to be constant.

JP 2012-222908 A

  In the power control system described in Patent Document 1, the stability of the power system is considered first. However, there is a demand from the owner of the power generation device to obtain as much profit as possible by selling the generated power efficiently.

  The present invention has been made in view of such circumstances, and provides a control device and a control method for a power control system that can expect not only the stability of the power system but also the profit of the owner of the power generation device. The purpose is to provide.

  According to a first aspect of the present invention, there is provided a power generation means for generating power using natural energy, a power storage means connected between the power generation means and a power system, and a power conversion means for controlling charging / discharging of the power storage means. A power control system control device comprising: a determination unit that determines whether or not the power storage unit is in a chargeable / dischargeable state; a price comparison unit that compares a power purchase price and a power sale price; and When the power storage means is in a chargeable / dischargeable state and the power selling price is lower than the power purchase price, the power storage means is charged / discharged so that both the purchased power and the sold power are zero. When the first mode to be performed is selected, the power storage means is at least in a dischargeable state, and the power sale price is higher than the power purchase price, the power generated by the power generation means is sold to the power system. And so that the electricity purchased is zero. Power control comprising mode selection means for selecting a second mode for discharging electric power means, and command output means for outputting a charge / discharge command based on the mode selected based on the mode selection means to the power conversion means It is the control unit of the system.

According to the control device of the power control system, when the power storage means is in a chargeable / dischargeable state, the power sale price is compared with the power purchase price, and when the power purchase price is higher than the power sale price. When charge / discharge control is performed so that the power sold to the grid power and the power purchased from the grid power are zero using charge / discharge of the power storage means as much as possible, and the power selling price is higher than the power purchased price, Electric power is sold as much as possible, and charge / discharge control of the power storage device is performed so that power is not purchased. In this way, since the charge / discharge mode is switched according to the comparison result between the power purchase price and the power sale price, it is possible to effectively sell power and obtain profits.
The sold power is the power transmitted from the power generation device or the storage battery to the power system, and the purchased power is the power transmitted from the power system to the storage battery or the load.

  The control device of the power control system has output recommendation information in which a voltage value of the power system, a recommended power sale value, and a recommended power purchase value are associated, and a recommended power sale value according to the voltage value of the power system. Or a recommended output value acquisition means for acquiring a recommended power purchase value, wherein the command output means refers to the recommended power sale value or the recommended power purchase value, and issues a charge / discharge control command for the power storage means according to the mode. It may be created. Here, the recommended power sale value is set when the voltage value of the power system is smaller than a predetermined lower limit value, and the recommended power purchase value is set when the voltage value of the power system is larger than a predetermined upper limit value. Is set.

  In this way, the charge / discharge control command is generated taking into account the recommended power purchase value or the recommended power sale value according to the system voltage value, so it is possible to create a charge / discharge control command that also contributes to the stability of the system voltage It becomes.

In the control device of the power control system, the determination unit, for example, when the temperature of the power storage unit is within a predetermined allowable temperature range and the remaining capacity is within a predetermined allowable remaining capacity range, It is determined that the means is in a chargeable / dischargeable state.
In the control device of the power control system, the command output unit prohibits charging when, for example, the temperature of the power storage unit is within the allowable temperature range and the remaining capacity exceeds an allowable upper limit value. To do. As a result, the remaining capacity can be prevented from further increasing. Further, in the control device of the power control system, the command output means may discharge, for example, when the temperature of the power storage means is within the allowable temperature range and the remaining capacity is less than an allowable lower limit value. Is prohibited. This can prevent the remaining capacity from further decreasing.

The 2nd mode of the present invention is an electric power control system provided with the above-mentioned control device.
According to a third aspect of the present invention, there is provided power generation means for generating power using natural energy, power storage means connected between the power generation means and a power system, and power conversion means for controlling charge / discharge of the power storage means. And determining whether or not the power storage means is in a chargeable / dischargeable state, and when the power storage means is at least in a dischargeable state, When the power sale price is higher than the power purchase price, the power generated by the power generation means is sold to the power system, and the power storage means is discharged so that the power purchase power becomes zero. It is the control method of the electric power control system to perform.

  According to the present invention, it is possible to increase the profit of the owner of the power generation device.

It is the figure which showed the whole schematic structure of the electric power control system which concerns on one Embodiment of this invention. It is a functional block diagram of the control apparatus shown in FIG. It is the figure which showed an example of output restriction information. It is the figure which showed an example of the electric power of P1 point in FIG. It is a figure for demonstrating charge prohibition mode. It is a figure for demonstrating discharge prohibition mode. It is a figure for demonstrating electric power leveling mode. It is the flowchart which showed the control method of the electric power control system which concerns on one Embodiment of this invention. It is the flowchart which showed the control method of the electric power control system which concerns on one Embodiment of this invention.

Hereinafter, an embodiment of a control device and a control method of a power control system according to the present invention will be described with reference to the drawings.
FIG. 1 is a diagram illustrating an overall schematic configuration of a power control system according to the present embodiment. As shown in FIG. 1, the power control system 1 includes a power generation device 2 that generates power using natural energy, a power storage device 3 connected between the power generation device 2 and the power system 5, and charging of the power storage device 3. A power conversion device 4 that controls discharge and a control device 10 are provided. The power conversion device 4 is, for example, a bidirectional inverter device that converts power stored in the power storage device 3 into alternating current and discharges it, and converts AC power into direct current power and charges the power storage device 3. A load 6 is connected between the power generator 2 and the power system 5.

  The control device 10 is, for example, a microcomputer that is integrated with the power conversion device 4, and includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a computer-readable recording medium, and the like (not shown). . A series of processing steps for realizing various functions to be described later are recorded in a recording medium or the like in the form of a program, and the CPU reads the program into a RAM or the like to execute information processing / arithmetic processing. Thus, various functions described later are realized.

FIG. 2 is a functional block diagram showing functions provided in the control device 10. As shown in FIG. 2, the control device 10 includes a temperature determination unit (determination unit) 11, a remaining capacity determination unit (determination unit) 12, a recommended output value acquisition unit 13, a price comparison unit 14, a mode selection unit 15, and a charging unit. A discharge command creation unit (command creation means) 16 is provided.
Temperature determination unit 11 compares the temperature of power storage device 3 with a preset upper limit temperature, and outputs the comparison result to mode selection unit 15.
The remaining capacity determination unit 12 determines whether or not the remaining capacity of the power storage device is within a predetermined charge / discharge allowable range, and if the remaining capacity is not within the charge / discharge allowable range, It is determined whether it is less than the lower limit remaining capacity, and this determination result is output to the mode selection unit 15.

  The recommended output value acquisition unit 13 holds output recommendation information in which the voltage value of the power system 5 (hereinafter referred to as “system voltage value”), the recommended power sale value, and the recommended power purchase value are associated with each other. The recommended power selling value or the recommended power purchasing value is acquired. FIG. 3 shows an example of output recommendation information. In FIG. 3, the horizontal axis represents the system voltage value, and the vertical axis represents the recommended output value. As shown in FIG. 3, it is divided into a power sale recommendation area, a normal area, and a power purchase recommendation area according to the value of the system voltage. In the normal region, the system voltage is set to a voltage range (for example, 95 V to 107 V) in the vicinity of a predetermined reference value (for example, 101 V).

In the region where the system voltage is lower than the normal region, power selling is recommended as a power selling recommended region. Specifically, the recommended power sale value is set to a higher value as the system voltage value is lower. As described above, in a region where the system voltage value is lower than the normal region, power purchase that is a factor for reducing the system voltage value is restricted, and power sale is recommended, so that the system voltage value is stabilized.
In addition, in a region where the system voltage value is higher than that in the normal region, power sale is restricted and power purchase is recommended as a power purchase recommendation region. Specifically, the recommended power purchase value is set higher as the system voltage value increases. As described above, in a region where the system voltage value is higher than the normal region, power selling that is a factor for increasing the system voltage value is limited and power purchase is recommended, which leads to a stable system voltage value.

  The price comparison unit 14 compares the power purchase price with the power sale price. The power selling price is often set uniformly according to, for example, the type of the power generation device 2, and in that case, the information may be registered in advance. In addition, as for the power purchase price, since the unit price generally varies depending on the contract with the electric power company and also changes depending on the time zone, information on the corresponding power purchase price is acquired and stored in advance.

The mode selection unit 15 has various modes such as a charge / discharge inhibition mode, a charge inhibition mode (second mode), a discharge inhibition mode, and a power leveling mode (first mode). One of the charge / discharge modes is selected according to the determination results of the capacity determination unit 12 and the price comparison unit 14.
Hereinafter, each charge / discharge mode will be described with reference to the drawings.

(Charge / Discharge prohibited mode)
The charge / discharge prohibit mode is a mode for prohibiting charge / discharge. Therefore, when this mode is selected, the power conversion device 4 is stopped, and charging / discharging of the power storage device 3 is also stopped.

(Charge prohibition mode)
The charge prohibition mode is a mode for prohibiting charging and controlling discharging so that the purchased power is zero. However, as described above, when the recommended power purchase value is set in relation to the system voltage, charge / discharge control is performed so as to allow power purchase within the range of the recommended power purchase value.
For example, it is assumed that the power at the point P1 in FIG. 1 changes as shown in FIG. In FIG. 4, the horizontal axis represents time, the vertical axis represents power, the positive side means the power selling side, and the negative side means the power buying side. The same applies to FIGS. 5 to 7. When neither the recommended power sale value nor the recommended power purchase value is set (that is, when the system voltage value is in the normal region), the waveform is as shown in FIG. In FIG. 5, the thick solid line is the power at point P2 in FIG. 1, in other words, the charge / discharge power of power storage device 3, the thick dotted line is the power at point P3 in FIG. 1, and the thin solid line is shown for reference. The power at the point P1. 6 and 7, the thick solid line means the power at the point P2, the thick dotted line means the power at the point P3, and the thin solid line means the power at the point P1.
Further, when the recommended power sale value is set, the waveform is as shown in FIG. 5B, and when the recommended power purchase value is set, the waveform is as shown in FIG. It becomes. In FIG. 5B, the power sale power exceeds the recommended power sale value because charging is prohibited.
Here, the sold power is power transmitted from the power generation device or the storage battery to the power system, and the purchased power is power transmitted from the power system to the storage battery or the load.
As described above, in the charge prohibition mode, charging is prohibited, so that the sold power can be positively output to the power system 5 without being limited by the recommended power sale value.

(Discharge prohibited mode)
The discharge prohibition mode is a mode in which the charging is controlled so that the electric power sold is zero while the discharge is prohibited. However, as described above, when the recommended power sale value is set in relation to the system voltage, charge / discharge control is performed so as to allow power purchase within the range of the recommended power sale value.
For example, if the power at the point P1 in FIG. 1 has the waveform shown in FIG. 4, if neither the recommended power sale value nor the recommended power purchase value is set, the waveform is as shown in FIG. When the recommended power sale value is set, the waveform is as shown in FIG. 6B, and when the recommended power purchase value is set, the waveform is as shown in FIG. It becomes. In FIG. 6C, the purchased power exceeds the recommended power purchase value because discharge is prohibited.

(Power leveling mode)
The power leveling mode is basically a mode in which the power storage device 3 is charged and discharged so that both the purchased power and the sold power are zero. However, as described above, when the recommended power purchase value or the recommended power sale value is set in relation to the system voltage, charge / discharge control is performed within the range of the recommended power purchase value or the recommended power sale value.
For example, when the power at the point P1 in FIG. 1 has the waveform shown in FIG. 4, if neither the recommended power sale value nor the recommended power purchase value is set, the waveform is as shown in FIG. When the recommended power sale value is set, the waveform is as shown in FIG. 7B. When the recommended power purchase value is set, the waveform is as shown in FIG. 7C. It becomes.

  When the temperature determination unit 11 determines that the temperature of the power storage device 3 exceeds the predetermined upper limit temperature, the mode selection unit 15 selects the charge / discharge inhibition mode. Further, when the temperature of the power storage device 3 is equal to or lower than the upper limit temperature and the remaining capacity of the power storage device 3 exceeds the upper limit remaining capacity, the charging prohibit mode is set, and the temperature of the power storage device 3 is equal to or lower than the upper limit temperature. When the remaining capacity of the apparatus is less than the lower limit remaining capacity, the discharge inhibition mode is selected.

  When the temperature of the power storage device 3 is equal to or lower than the upper limit temperature and the remaining capacity of the power storage device 3 is within the allowable remaining capacity, the result of the price comparison unit 14 is referred to and the power purchase price is the power selling price. If the power selling price is higher than the power purchase price, the charge leveling mode is selected. When the power selling price and the power buying price are the same price, the power leveling mode is selected.

  The charge / discharge command creation unit 16 creates a charge / discharge command according to the mode selected based on the mode selection unit 15 and the recommended output value acquired by the recommended output value acquisition unit 13, and generates the charge / discharge command. Output to. That is, the charge / discharge command creation unit 16 generates a charge / discharge command according to the power at the point P1, the recommended output value acquired by the recommended output value acquisition unit 13, and the mode selected by the mode selection unit 15, and uses this as the power. Output to the converter 4.

  Next, processing executed by the control device of the power control system having the above configuration will be described with reference to FIGS. 8 and 9. For example, the control device 10 controls the power conversion device 4 by repeatedly executing the flowcharts shown in FIGS. 8 and 9 at predetermined time intervals.

  First, information such as the temperature and remaining capacity information of the power storage device 3, the system voltage value, and the power at the point P1 is acquired (step SA1). Next, it is determined whether or not the temperature of the power storage device 3 is equal to or higher than a predetermined upper limit value (step SA2). As a result, if the temperature of power storage device 3 is equal to or higher than the upper limit (“YES” in step SA2), the charge / discharge inhibition mode is selected (step SA13), and the process ends. On the other hand, when the temperature of power storage device 3 is equal to or lower than the upper limit value ("NO" in step SA2), a recommended output value corresponding to the system voltage value is acquired (step SA3).

  Next, it is determined whether or not the remaining capacity of the power storage device 3 is within a predetermined charge / discharge allowable range (step SA4). As a result, when the charge / discharge allowable range is not satisfied (“NO” in step SA4), it is determined whether the remaining capacity is equal to or greater than the upper limit remaining capacity (step SA5 in FIG. 9). As a result, if it is equal to or greater than the upper limit remaining capacity (“YES” in step SA5), the charge prohibition mode is selected (step SA6). On the other hand, if it is less than the upper limit remaining capacity in step SA5, the discharge inhibition mode is selected (step SA7).

If it is determined in step SA4 that the remaining capacity is within the charge / discharge allowable range (“YES” in step SA4), it is determined whether the power purchase price is higher than the power sale price (step SA8). ). As a result, if the power purchase price is the same as the power sale price or the power purchase price is higher than the power sale price (“NO” in step SA8), the power leveling mode is selected (step SA9), and the power sale price is selected. Is higher than the power purchase price (“YES” in step SA8), the charging prohibition mode is selected (step SA10). Thus, when the mode is selected, a charge / discharge command is created with reference to the selected mode and the recommended output value (step SA11), and is output to the power converter (step SA12).
Thereby, by controlling a power converter based on charging / discharging instruction | command, charging / discharging according to charging / discharging mode is made, and desired electric power purchase and power sale control are performed.

As described above, according to the power control system, the control device, and the control method according to the present embodiment, when the remaining capacity is within the charge / discharge allowable range, the power purchase price is compared with the power sale price. If the power selling price is high, the charging prohibition mode in which power is actively sold is selected, so that the profit of the owner of the power storage device 3 can be pursued. In addition, if the power selling price is equal to or less than the power purchasing price, the power leveling mode in which the power output to the power system 5 is zero is selected without actively selling power. An adverse effect on the system 5 can be prevented. Furthermore, since the recommended output value corresponding to the system voltage value is acquired and charge / discharge control is performed according to this recommended output value, for example, when the system voltage is high, the power sale is suppressed and the purchase of power is recommended. On the contrary, when the system voltage is low, charge / discharge control is performed so as to suppress power purchase and recommend power sale. Thereby, an electric power system can be contributed to stabilization.
Further, when the remaining capacity of the power storage device 3 is not within the allowable charge / discharge range, the charge prohibition mode or the discharge prohibition mode is selected according to the remaining capacity, so that the remaining capacity is quickly transferred to the charge / discharge allowable range. Can be made.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the invention.

DESCRIPTION OF SYMBOLS 1 Power control system 2 Power generation device 3 Power storage device 4 Power conversion device 5 Power system 6 Load 10 Control device 11 Temperature judgment part 12 Remaining capacity judgment part 13 Output recommendation value acquisition part 14 Price comparison part 15 Mode selection part 16 Charge / discharge command preparation Part

Claims (7)

A control device for a power control system, comprising: power generation means for generating power using natural energy; power storage means connected between the power generation means and a power system; and power conversion means for controlling charge / discharge of the power storage means. Because
Determining means for determining whether or not the power storage means is in a chargeable / dischargeable state;
A price comparison means for comparing the power purchase price and the power sale price;
When the power storage means is in a chargeable / dischargeable state and the power sale price is lower than the power purchase price, charging / discharging of the power storage means is performed so that both the purchased power and the sold power are zero. When the first mode is selected, the power storage means is at least in a dischargeable state, and the power sale price is higher than the power purchase price, the generated power of the power generation means is sold to the power system. Mode selection means for selecting a second mode for discharging the power storage means so that the purchased electric power is zero;
A control device for a power control system, comprising: command creation means for creating a charge / discharge command based on a mode selected based on the mode selection means. The output that holds output recommendation information in which the voltage value of the power system is associated with the recommended power sale value and the recommended power purchase value, and obtains the recommended power sale value or the recommended power purchase value according to the voltage value of the power system. With recommended value acquisition means,
The command output means refers to the recommended power sale value or the recommended power purchase value, and creates a charge / discharge control command for the power storage means according to the mode,
The recommended power sale value is set when the voltage value of the power system is smaller than a predetermined lower limit value, and the recommended power purchase value is set when the voltage value of the power system is larger than a predetermined upper limit value. The control apparatus of the power control system according to claim 1.   The determination unit determines that the power storage unit is in a chargeable / dischargeable state when the temperature of the power storage unit is within a predetermined allowable temperature range and the remaining capacity is within a predetermined allowable remaining capacity range. The control device of the power control system according to claim 1 or 2.   4. The power control system according to claim 3, wherein the command output unit prohibits charging when the temperature of the power storage unit is within the allowable temperature range and the remaining capacity exceeds an allowable upper limit value. Control device.   5. The command output unit according to claim 3, wherein the command output unit prohibits discharge when the temperature of the power storage unit is within the allowable temperature range and the remaining capacity is less than an allowable lower limit value. Control device for power control system.   A power control system comprising the control device according to any one of claims 1 to 5. A control method for a power control system, comprising: power generation means for generating power using natural energy; power storage means connected between the power generation means and a power system; and power conversion means for controlling charge / discharge of the power storage means. Because
Determining whether the power storage means is at least in a dischargeable state;
When the power storage means is at least in a dischargeable state, the power purchase price is compared with the power sale price, and when the power sale price is higher than the power purchase price, the power generated by the power generation means is supplied to the power system. A control method of a power control system for selling power and discharging the power storage means so that the purchased power becomes zero.

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