WO2023054335A1

WO2023054335A1 - Power supply facility

Info

Publication number: WO2023054335A1
Application number: PCT/JP2022/035884
Authority: WO
Inventors: 直充吉田; 玲彦叶田; 輝菊池; 尊衛嶋田; 一正井出; 拓也石川
Original assignee: 株式会社日立パワーソリューションズ
Priority date: 2021-09-28
Filing date: 2022-09-27
Publication date: 2023-04-06
Also published as: JP2023048576A

Abstract

Provided is a power supply facility in which each DC apparatus stably supplies DC power. A power supply facility according to the present invention comprises a first conversion device that is disposed between an AC power line and a DC power line and that carries out power conversion, a second conversion device that is disposed between the DC power line and a storage battery and that carries out power conversion, and a third conversion device that is disposed between the DC power line and a renewable energy power supply and that carries out power conversion, said power supply facility being characterized in that: the first conversion device controls the voltage of the DC power line to be a first voltage; and when the first conversion device fails to control the voltage of the DC power line to be the first voltage and the voltage of the DC power line exceeds a second voltage which is set higher than the first voltage, the second conversion device controls the voltage of the DC power line to be the second voltage.

Description

Power supply equipment

The present invention relates to a power supply facility that stably supplies power generated by a renewable energy power generation device to a load.

Patent Document 1 is known as a power supply facility that stably supplies power generated by a renewable energy power generation device to a load. Patent Document 1 states, "The power control device includes a control unit configured to be able to control a bidirectional inverter connected between the AC side and the DC side, and the control unit controls the power generated by the renewable energy power generation device. obtaining predicted values at a plurality of times between a first time and a second time for each of the power consumption and the power consumption of the load, assuming a target charging amount of the power storage device at the second time, , based on the target charge amount at the first time calculated by updating the target charge amount at each time by applying the predicted value at each time so as to go back from the second time to the first time, both A power control device, a power control method, a bidirectional inverter, and a power control system for causing a bidirectional inverter to perform a charging operation or a discharging operation.

Japanese Patent Application Laid-Open No. 2021-52488

According to Patent Document 1, a bidirectional inverter performs a charging operation or a discharging operation based on a target charge amount of a power storage device assumed from each predicted value of the power generation amount of a renewable energy power generation apparatus and the power consumption amount of a load. By executing it, the storage battery can be used effectively, but when the predicted value and the actual power deviate due to a sudden change in the generated power due to weather changes or a sudden change in the load, the voltage value of the DC connection is set to a predetermined value or within a predetermined range. There is a problem that can deviate from

The voltage value of the DC connection may deviate from a predetermined value or a predetermined range, and if the voltage value deviates from the predetermined range, failure of equipment connected to the DC power line is caused.

In view of this problem, it is an object of the present invention to provide a power supply facility in which each DC device in the power supply facility supplies DC power stably.

From the above, in the present invention, "a first conversion device that is arranged between an AC power line and a DC power line and performs power conversion, and a second conversion device that is arranged between the DC power line and a storage battery and performs power conversion and a third conversion device disposed between a DC power line and a renewable energy power source to perform power conversion, wherein the first conversion device converts the voltage of the DC power line to a first voltage and the second converter sets a second voltage in which the first converter cannot control the voltage of the DC power line to the first voltage and the voltage of the DC power line is set higher than the first voltage A power supply facility characterized by controlling the voltage of a DC power line to a second voltage when the voltage is exceeded.

Further, in the present invention, "a first conversion device that is arranged between an AC power line and a DC power line and performs power conversion, and a second conversion device that is arranged between the DC power line and a storage battery and performs power conversion, A third conversion device arranged between the DC power line and the renewable energy power source to perform power conversion, and a power supply that gives a control command to the first conversion device, the second conversion device, and the third conversion device. A power supply facility including a facility control unit, wherein the power supply facility control unit transmits a maximum power conversion capacity command as a control command to the first conversion device, and the first conversion device transmits the maximum power conversion capacity command A power supply facility characterized by controlling the voltage of a DC power line to a first voltage within the power capacity designated by a command.

Further, in the present invention, "a first conversion device that is arranged between an AC power line and a DC power line and performs power conversion, and a second conversion device that is arranged between the DC power line and a storage battery and performs power conversion, A power supply facility including a third conversion device that is arranged between a DC power line and a renewable energy power source and performs power conversion, wherein the first conversion device, the second conversion device, and the third conversion device and a power supply facility control unit that gives a control command, and is provided in each of the first conversion device, the second conversion device, and the third conversion device, and the voltage of the DC power line is the first voltage, the second voltage, A power supply comprising: a voltage regulator for controlling each voltage to a third voltage, wherein the voltage regulator controls the voltage of the DC power line to any one of the first voltage, the second voltage, and the third voltage. equipment.

According to the present invention, each DC device in the power supply facility can actively switch control by referring to the voltage value of the DC power line without using an external command, thereby stably supplying DC power.

The figure which shows the structural example of the power supply equipment which concerns on Example 1 of this invention. FIG. 4 is a diagram showing control example 1 of the power of each part and the voltage VD of the DC power line when the present invention is applied. FIG. 4 is a diagram showing control example 2 of the power of each part and the voltage VD of the DC power line when the present invention is applied. FIG. 10 is a diagram showing control example 3 of the power of each part and the voltage VD of the DC power line when the present invention is applied. FIG. 10 is a diagram showing control example 4 of the power of each part and the voltage VD of the DC power line when the present invention is applied. FIG. 10 is a diagram showing control example 5 of the power of each part and the voltage VD of the DC power line when the present invention is applied. The figure which shows the other structural example of the power supply equipment which concerns on Example 1 of this invention. The figure which shows the other structural example of the power supply equipment which concerns on Example 1 of this invention. The figure which shows the structural example of the power supply equipment which concerns on Example 2 of this invention. The figure which shows the control example of each part electric power and the voltage VD of a DC power line at the time of Example 2 application of this invention. The figure which shows the structural example of the power supply equipment which concerns on Example 3 of this invention. The figure which shows the control example of each part electric power and the voltage VD of a DC power line at the time of Example 3 application of this invention. The figure which shows the structural example of the power supply equipment which concerns on Example 4 of this invention. The figure which shows the structural example of the power supply equipment which concerns on Example 5 of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the present invention is not limited to the following examples. Those skilled in the art can make various additions, modifications, etc. within the scope of the present invention.

FIG. 1 shows a configuration example of a power supply facility according to Embodiment 1 of the present invention. The power supply facility 1 includes a solar cell 2 , a first DC/DC converter 3 , a power storage device 4 , an AC/DC inverter 5 , a DC power line 6 , and a power supply facility controller 7 . A solar cell 2 is connected to a first DC/DC converter 3 . A DC power line 6 connects the output end of the first DC/DC converter 3, the power storage device 4, and the DC output end of the AC/DC inverter 5 in parallel. An AC output terminal of the AC/DC inverter 5 is connected to a distribution line 8 connected to an AC power supply 9, and the AC/DC inverter 5 is capable of bi-directional power conversion. An AC load 10 is connected to the distribution line 8 .

The power storage device 4 is composed of a storage battery 41 and a DC/DC converter 42 . The DC/DC converter 42 is a bidirectional power conversion circuit, and can charge and discharge the storage battery 41 under the control of the DC/DC converter 42 . The storage battery 41 is, for example, a secondary battery such as a lithium ion battery or a nickel metal hydride battery. The power storage device 4 may be a stationary facility, or the storage battery 41 may be an electric vehicle such as an electric vehicle, and the DC/DC converter 42 may be a stationary charger/discharger.

In addition, in the power supply facility 1 of FIG. 1, the solar cell 2 may generally be a renewable energy power source such as photovoltaic power generation or wind power generation, and the case of photovoltaic power generation is shown here. In the case of wind power generation, the wind power generation itself outputs alternating current, so the first DC/DC converter 3 is configured as an AC/DC inverter. Although there is such a structural difference, the present invention can be applied to any of the above renewable energy power sources.

As illustrated in FIG. 1, the power supply facility 1 includes a first conversion device (AC/DC inverter 5) that is arranged between the AC power line 8 and the DC power line 6 to perform power conversion, the DC power line 6 and the storage battery 4 A second conversion device (DC/DC converter 42) that is placed between the DC power line 6 and the renewable energy power supply 2 to perform power conversion, and a third conversion device (the third 1 DC/DC converter 3).

In the equipment configuration related to the power supply facility 1, in the present invention, as a control function for controlling this, the power supply facility control unit 7 and the

voltage adjustment units

5V, 3V, and 4V arranged for each of the

individual converters

3, 42, and 5 It has two types of control by The

voltage regulators

5V, 3V and 4V may have their functions in control circuits (not shown) of the

converters

3, 42 and 5, respectively. Although the details will be described later, the power supply facility control unit 7 performs long-cycle control in units of several seconds or minutes on the three sets of

converters

3, 42, and 5 described above. , 42 and 5 are provided for short-cycle control. Short-cycle control is performed in a shorter cycle than long-cycle control.

The power supply facility control unit 7 operates as an EMS (Energy Management System). That is, the power received from the AC power supply 9, the power consumption of the load 10, the power generated by the solar cell 2, the SOC (State of Charge) of the storage battery 41, etc. are measured (not shown), and the rated power of each device and the solar power The power flow in the power supply facility 1 is determined from the viewpoint of the predicted power generation of the battery 2, the predicted power consumption of the load 10, the SOC of the storage battery 41, and life/deterioration management.

Then, a charge/discharge power command or a charge/discharge current command, a charge/discharge power upper/lower limit value or a charge/discharge current upper/lower limit value, and an SOC upper/lower limit value are commanded to the power storage device 4 as control commands. command the upper and lower limits of the converted power as a control command. Commands are issued at regular intervals (for example, at intervals of one minute) through wired communication or wireless communication. Further, the power supply facility control unit 7 instructs the first DC/DC converter 3, the power storage device 4, and the AC/DC inverter 5 to start and stop operations as control commands.

These commands given from the power supply facility control unit 7 to the first DC/DC converter 3, the power storage device 4, and the AC/DC inverter 5 are transmitted in several tens of seconds or on the order of minutes. It is a long-cycle one that occurs.

The first DC/DC converter 3 performs maximum power point tracking (MPPT) control on the power generated by the connected solar cell 2 and outputs it to the DC power line 6 . In addition, the power storage device 4 performs charging/discharging power or charging/discharging current control in accordance with a command from the power supply facility control unit 7 .

On the other hand, in the control by the

voltage adjustment units

5V, 3V, and 4V arranged for the

individual converters

3, 42, and 5, which is the other control system, the voltage VD of the DC power line 6 is detected and detected. They are controlled to respective set voltage values VD1, VD2 or VD4, VD3. A voltage value VD1 is set in the voltage adjustment section 5V of the AC/DC inverter 5, voltage values VD2 and VD4 are set in the voltage adjustment section 4V of the DC/DC converter 42, and the voltage of the first DC/DC converter 3 A voltage value VD3 is set in the adjusting section 3V.

At this time, the magnitude relationship of each voltage value is voltage value VD3>voltage value VD2>voltage value VD1. Although it is controlled to VD1, when the voltage VD of the DC power line 6 rises, it is controlled to the voltage value VD2 by the control by the voltage adjustment unit 4V of the DC/DC converter 42, and when the voltage VD of the DC power line 6 further rises, the 1 is controlled by the voltage adjustment unit 3V of the DC/DC converter 3 of 1 to the voltage value VD3. The voltage value VD4 will be described later.

Although it may not be possible to control the voltage to the target value VD as a result, the voltage control itself is continued. The AC/DC inverter 5 always tries to control the voltage to VD1, but the conversion power reaches the upper limit, resulting in P3+P4>P5, and the voltage rises without being controlled to VD1. At that time, the power storage device starts voltage control to VD2, but the AC/DC inverter 5 continues the control operation (control to VD1). This also applies to power storage device 4 .

By applying the two types of control systems described above, the three sets of

converters

3, 42, and 5 control the DC power line 6 within the range of control commands related to various long-cycle restrictions set by the power supply facility control unit 7. Three sets of

converters

3, 42, 5 will perform the voltage control.

Specifically, this sharing control is executed as follows according to the operation status of the power supply facility 1. First, AC/DC inverter 5 controls voltage VD of DC power line 6 to voltage value VD1. The voltage value VD1 is, for example, 350V. AC/DC inverter 5 controls AC output power P5 so that voltage VD of DC power line 6 is controlled to voltage value VD1. At this time, the sum of the output power P3 of the first DC/DC converter 3 and the discharge power P4 of the power storage device 4 is equal to the AC output power P5 of the AC/DC inverter 5 (P3+P4=P5). The first voltage VD1 is the maximum value of the voltage range common to the input voltage ranges of the AC/DC inverter 5, the first DC/DC converter 3, and the power storage device 4 connected to the DC voltage line 6. , the voltage except for the minimum value.

When the voltage VD of the DC power line 6 is higher than the voltage value VD1, the AC/DC inverter 5 outputs AC power to the distribution line 8 side and feeds it to the load 10 to increase the voltage VD of the DC power line 6 to the voltage value VD1. lower to When the voltage VD of the DC power line 6 is lower than the voltage value VD1, the AC/DC inverter 5 receives the power of the AC power supply 9 from the distribution line 8 side, and supplies the power to the power storage device 4, whereby the DC power line 6 is increased to a voltage value VD1.

As described above, the AC/DC inverter 5 can control the voltage VD of the DC power line 6 to the voltage value VD1 by controlling the converted power. In this embodiment, power conversion from the DC side to the AC side is positive, and power conversion from the AC side to the DC side is negative.

However, the power that the AC/DC inverter 5 can convert is limited by the rated power. When the power supply facility control unit 7 manages the reverse flow power to the AC power supply 9 and the received power, the AC/DC inverter 5 is commanded by the power supply facility control unit 7 for the upper and lower limits of the converted power. Therefore, the upper limit of the converted power of the AC/DC inverter 5 is the minimum value of the rated power of the AC/DC inverter 5 and the upper limit of the converted power commanded from the power supply facility control unit 7. The lower limit of the power is the maximum value of the rated power of the AC/DC inverter 5×(−1) and the lower limit of the converted power commanded from the power supply facility control unit 7 . Depending on the upper and lower limits of the converted power, the AC/DC inverter 5 may not be able to control the voltage VD of the DC power line 6 to the voltage value VD1.

FIG. 2 shows control example 1 of the power of each part and the voltage VD of the DC power line when the present invention is applied. First, here, the output power P3 of the first DC/DC converter 3, the discharge power P4 of the power storage device 4, and the AC output power P5 of the AC/DC inverter 5 are used as the power for each part of the power supply facility 1, as shown in FIG. listed above. However, in this case, the converted power P5 of the AC/DC inverter 5 has a positive output to the AC side and a negative input (power reception) from the AC side. Also, the charge/discharge power P4 of the power storage device 4 is positive when discharged and negative when charged. Assume that the output P3 of the first DC/DC converter 3 is positive.

In addition, the lower part of FIG. 2 shows the relationship between the time change of the voltage VD of the DC power line and the voltage values VD1, VD2, and VD3 set for each of the three sets.

According to the time notation shown on the horizontal axis in the upper part of FIG. 2, the control cycle of the power supply facility control unit 7 is T, and after giving a command at time 0, it shows that a command is given again at time T. there is On the other hand, the times T1 to T6 written within the period T are the times when various events occur in the three sets of

converters

3, 42, and 5 in the power supply facility 1. As is clear from this, It can be said that the control of the power supply facility 1 is long-cycle control, and the control by the

voltage regulators

5V, 3V, and 4V arranged for the

individual converters

3, 42, and 5 is short-cycle control.

In addition, in the control by the two systems shown in FIG. operated within the limits set. However, with respect to renewable energy sources, it is preferable to give priority to outputting the amount of power generation as it is, and not to impose any particular restrictions.

In the illustrated example, at time 0, the upper limit of the converted power of the AC/DC inverter 5 is set to 50 kW (at time 0, the converted power P5 is 40 kW) by a command from the power supply facility control unit 7, and the power storage device 4 The charge/discharge power upper limit is set to 20 kW, and the charge/discharge power lower limit is set to -20 kW. However, in the illustrated example, the power storage device 4 is discharged at 20 kW in order to supply power to the load 10 . Also, at time 0, the output of the first DC/DC converter 3 is assumed to be 20 kW.

At this time, the total of the output P3 (20 kW) of the first DC/DC converter 3 and the discharged power P4 (20 kW) of the power storage device 4 is 40 kW, which is less than the upper limit of the converted power P5 of the AC/DC inverter 5. , the AC/DC inverter 5 can control the voltage VD of the DC power line 6 to the voltage value VD1 by converting the power by 40 kW.

From time 0 to time T1, when the output power of the first DC/DC converter 3 increases due to fluctuations in solar radiation, the AC/DC inverter 5 increases the converted power P5 to bring the voltage VD of the DC power line 6 to the first level. Control to voltage VD1. At time T1, the output power P3 of the first DC/DC converter 3 becomes 30 kW, and the converted power P5 of the AC/DC inverter 5 reaches the upper limit value of 50 kW.

After time T1, when the output power P3 of the first DC/DC converter 3 further increases, the AC/DC inverter 5 cannot increase the converted power P5 from 50 kW, and the voltage VD of the DC power line 6 becomes the first It rises from voltage VD1. Then, at time T2, it reaches a second voltage VD2 (for example, 370 V) that is higher than the first voltage VD1 and lower than the third voltage VD3.

When the voltage VD of the DC power line 6 is equal to or higher than the second voltage VD2, this state is detected by the voltage adjustment unit 4V of the DC/DC converter 42, and the power storage device 4 charges and discharges as instructed by the power supply equipment control unit 7. Power control is stopped and voltage control of the DC power line 6 is executed. Voltage control is performed, for example, by feedback control using the voltage VD of the DC power line 6 as a reference value.

At this time, in the present embodiment, the power storage device 4 performs voltage control with the second voltage VD2 as the target value. In addition, the power storage device 4 performs voltage control within a control range that complies with a discharge power equal to or higher than the charge/discharge power lower limit commanded by the power supply equipment control unit 7 or a discharge current equal to or higher than the charge/discharge current lower limit commanded. do. In this embodiment, it is assumed that -20 kW is commanded as the charge/discharge power lower limit. The upper limit value of the discharge power or discharge current is the minimum value between the instructed charge/discharge power upper limit value and 0 kW, or the minimum value between the instructed charge/discharge current upper limit value and 0 A.

Also, voltage control is executed only when the SOC of the storage battery 41 is less than the SOC upper limit commanded by the power supply facility control unit 7 . This operation prevents overvoltage from being applied to equipment connected to the DC power line 6 . After time T2, the power storage device 4 executes voltage control with the second voltage as a target value by decreasing the discharging power and increasing the charging power.

At time T3, the discharged power of the power storage device 4 reaches -20 kW (charged power of 20 kW). After time T3, even if the output power P3 of the first DC/DC converter 3 further increases, the power storage device 4 cannot increase the charging power. It further increases, and at time T4, it reaches a third voltage VD3 (for example, 390 V) that is higher than the second voltage VD2 and lower than the maximum DC voltage. The maximum DC voltage is the input voltage upper limit value of the device with the lowest withstand voltage among the AC/DC inverter 5, the first DC/DC converter 3, and the power storage device 4 connected to the DC voltage line 6.

As shown in the lower part of FIG. 2, in the above operation, the relationship between the second voltage VD2 and the third voltage VD3 is set such that the third voltage VD3 is higher than the second voltage VD2. This means that control switching of the first DC/DC converter 3 is performed after control switching of the power storage device 4 . With this setting, the first DC/DC converter 3 switches from MPPT control to voltage control, and as a result, the means for suppressing photovoltaic power generation can be used as a final means, and power generation by the solar cell 2 can be continued as much as possible.

If the magnitude relationship of these voltages is switched so that the second voltage VD2 is set higher than the third voltage VD3 and the third voltage VD3 is set higher than the first voltage VD1, the power storage device 4 switches the control to charge the battery. Power generation by the solar cell 2 is suppressed before the power is increased, and the power generation capacity of the solar cell 2 is wasted.

When the voltage VD of the DC power line 6 is equal to or higher than the third voltage VD3, this state is detected by the voltage adjustment section 3V of the first DC/DC converter 3, and the first DC/DC converter 3 stops MPPT control. and voltage control of the DC power line 6 is executed. At this time, in this embodiment, the first DC/DC converter 3 performs voltage control with the third voltage VD3 as the target value. When the voltage VD of the DC power line 6 is equal to or higher than the third voltage VD3, there is no load or storage battery that can consume or charge all the power generated by the solar cell, so it is necessary to suppress the power generated by the solar cell 2. By switching to the voltage control described above, the power generation of the solar cell 2 is suppressed and the application of overvoltage to the equipment connected to the DC power line 6 is prevented.

After time T4, when the solar radiation decreases and the power generated by the solar cell 2 decreases, the voltage VD of the DC power line 6 drops below the third voltage VD3 at time T5. At this time, the first DC/DC converter 3 terminates the voltage control of the DC power line 6 and restarts the MPPT control. Note that the power storage device 4 continues to control the voltage VD of the DC power line 6 to the second voltage.

When the power generated by the solar cell 2 further decreases, the voltage VD of the DC power line 6 drops below the second voltage VD2 at time T6. At this time, the power storage device 4 terminates the voltage control of the DC power line 6 and restarts the charge/discharge power control instructed by the power supply equipment control unit 7 . After time T7, the voltage VD of the DC power line 6 is controlled to the first voltage VD1 by voltage control of the AC/DC inverter.

At time T when a new command is received from the power supply facility control unit 7, the voltage VD of the DC power line 6 is the first voltage VD1. At this time, the upper limit of the converted power of the AC/DC inverter 5 is updated to the minimum value of the rated power of the AC/DC inverter 5 and the upper limit of the converted power received from the power supply facility control unit 7 at time T. The lower limit of the converted power of the AC/DC inverter 5 is the maximum value of the rated power of the AC/DC inverter 5×(−1) and the lower limit of the converted power commanded from the power supply facility control unit 7 . Power storage device 4 operates according to the charge/discharge power command or the charge/discharge current command received from power supply facility control unit 7 at time T. FIG. In addition, the charge/discharge power upper/lower limit value, the charge/discharge current upper/lower limit value, and the SOC upper/lower limit value are updated. The power after time T in FIG. 2 shows the case where the upper limit of the converted power of AC/DC inverter 5 is updated to 50 kW, and power storage device 4 discharges with the new charge/discharge power command value of 10 kW.

FIG. 3 shows control example 2 of the power of each part and the voltage VD of the DC power line when the present invention is applied. Since the process up to time T5 is the same as control case 1 shown in FIG. 2, the description is omitted. In FIG. 3, at time T, the first DC/DC converter 3 performs MPPT control, and the power storage device 4 controls the voltage VD of the DC power line 6 to the second voltage. In this embodiment, it is assumed that the power storage device 4 is operating with a discharge power of 5 kW.

AC/DC inverter 5 and power storage device 4 receive a new command from power supply equipment control unit 7 at time T when voltage VD of DC power line 6 is greater than or equal to second voltage VD2 and less than third voltage VD3 , the upper limit of the converted power of the AC/DC inverter 5 is the minimum of the rated power of the AC/DC inverter 5 and the upper limit of the converted power received from the power supply facility control unit 7 at time T, as described in FIG. value. Assume that at time T in FIG. 3, the upper limit of the converted power of the AC/DC inverter 5 is updated to 50 kW.

The power storage device 4 updates the charge/discharge power upper/lower limit value, the charge/discharge current upper/lower limit value, and the SOC upper/lower limit value to the new values received from the power supply facility control unit 7 . In addition, the power storage device 4 stores the charge/discharge power command or charge/discharge current command (referred to as a command value in the present embodiment) received from the power supply facility control unit 7 at time T, and the actual charge/discharge power at time T or The charge/discharge current (referred to as the actual value in this embodiment) is compared with the power and current in the discharge direction as positive. Then, when the command value is smaller than the actual value, power storage device 4 terminates voltage control of DC power line 6 and performs charge/discharge power control according to the command value. If the command value is greater than the actual value, voltage control of the DC power line 6 is continued. However, the command value received at time T is retained and used as a command value from power supply equipment control unit 7 when power storage device 4 terminates voltage control of DC power line 6 and restarts charge/discharge power control.

In FIG. 3, the discharge power of the power storage device 4 immediately before time T is 5 kW. At time T, when power storage device 4 receives a charge/discharge power command of −10 kW for discharging (10 kW for charging) from power supply facility control unit 7, the command value is −10 kW, which is smaller than the actual value of 5 kW. terminates the voltage control of the DC power line 6 and implements the discharge power control according to the command value -10 kW. At this time, the voltage VD of the DC power line 6 is controlled to the first voltage VD1 by voltage control of the AC/DC inverter.

FIG. 4 shows control example 3 of the power of each part and the voltage VD of the DC power line when the present invention is applied. Since the process up to time T4 is the same as control case 1 shown in FIG. 2, the description is omitted. In FIG. 4, at time T, the first DC/DC converter 3 controls the voltage VD of the DC power line 6 to the third voltage VD3. It is assumed that the power storage device 4 operates with a discharge power of -20 kW (a charge power of 20 kW).

When time T arrives when the voltage VD of the DC power line 6 is equal to or higher than the third voltage VD3, and the AC/DC inverter 5 and the power storage device 4 receive a new command from the power supply facility control unit 7, the AC/DC inverter 5 is updated to the minimum value of the rated power of the AC/DC inverter 5 and the converted power upper limit value received from the power supply facility control unit 7 at time T, as described in FIG.

The power storage device 4 updates the charge/discharge power upper/lower limit value, the charge/discharge current upper/lower limit value, or the SOC upper/lower limit value to the new command received from the power supply facility control unit 7 . Further, power storage device 4 holds the charge/discharge power command or charge/discharge current command received from power supply facility control unit 7 at time T, and continues voltage control of DC power line 6 . The stored command value is used as a command value from the power supply facility control unit 7 when the power storage device 4 ends the voltage control of the DC power line 6 and restarts the charge/discharge power control.

Assume that at time T, the upper limit of the converted power of the AC/DC inverter 5 is updated to 50 kW, and the upper and lower limits of the charge/discharge power of the power storage device 4 are updated to the upper limit of 20 kW and the lower limit of −40 kW. Also, the charging/discharging power command for the storage device 4 is assumed to be -20 kW. At this time, since the voltage VD of the DC power line 6 is the third voltage VD3, the power storage device 4 continues to control the voltage of the DC power line 6 . Before time T, the charge/discharge power lower limit was −20 kW, but at time T, the charge/discharge power lower limit was updated to −40 kW, so the discharge power of power storage device 4 decreases. As a result of this operation, when the voltage VD of the DC power line 6 drops from the third voltage VD3 to the second voltage VD2 at time T7, the first DC/DC converter 3 ends the voltage control of the DC power line 6 and MPPT control is performed. to resume. Then, power storage device 4 continues to control voltage VD of DC power line 6 to the second voltage.
In addition to the above operation, the magnitude relationship of each voltage value is set as voltage value VD3>voltage value VD1>voltage value VD2, and normally the voltage VD of the DC power line 6 is determined by the voltage adjustment unit 4V of the DC/DC converter 42. Although it is controlled to the voltage value VD2 by control, when the voltage VD of the DC power line 6 rises, it is controlled to the voltage value VD1 by the control by the voltage adjustment unit 5V of the AC/DC inverter 5, and the voltage VD of the DC power line 6 is further increased. It is also possible to carry out a control operation in which the voltage is controlled to the voltage value VD3 by the control by the voltage adjusting section 3V of the first DC/DC converter 3 when it rises. In this operation, the power supply facility control unit 7 commands the AC/DC inverter 5 to output AC power, and the AC/DC inverter 5 follows the command when the voltage VD of the DC power line 6 is less than the voltage value VD1. AC output power P5 is output to the power line 8 . However, when the voltage adjustment unit 4V of the DC/DC converter 42 cannot control the voltage VD of the DC power line 6 to the voltage value VD2 and the voltage VD rises and exceeds the voltage value VD1, the voltage adjustment unit of the AC/DC inverter 5 The voltage VD is controlled to the voltage value VD1 by control with 5V. At this time, the AC/DC inverter 5 determines the AC output power P5 within the range of the converted power upper and lower limit values instructed by the power supply facility control unit 7 . By this operation, the power supply facility 1 that commands and controls the output power P5 to the AC power line 8 can be configured.

FIG. 5 shows control example 4 of the power of each part and the voltage VD of the DC power line when the present invention is applied. 2, 3, and 4 show the response when the voltage VD of the DC power line rises, while FIGS. 5 and 6 show the response when the voltage VD of the DC power line rises and falls.

In the example of FIG. 5, at time 0, the lower limit of the converted power of the AC/DC inverter 5 is set to −50 kW, and the charge/discharge power upper limit of the power storage device 4 is set to 60 kW, and the charge/discharge power lower limit is set to −60 kW. be. In addition, the power storage device 4 is discharged at -60 kW according to a command from the power supply equipment control unit 7 . Also, at time 0, the output of the first DC/DC converter 3 is assumed to be 20 kW. At this time, the sum of the output of the first DC/DC converter 3 and the discharge power of the power storage device 4 is -40 kW, which is equal to or higher than the lower limit of the converted power of the AC/DC inverter 5. Therefore, the AC/DC inverter 5 is - By converting 40 kW of power (receiving 40 kW of power from the distribution line 8), the voltage VD of the DC power line 6 can be controlled to the first voltage VD1.

From time 0 to time T1, when the output power of the first DC/DC converter 3 decreases due to fluctuations in solar radiation, the AC/DC inverter 5 reduces the converted power to convert the voltage VD of the DC power line 6 to the first voltage. Control to VD. At time T1, the output power of the first DC/DC converter 3 becomes 10 kW, and the converted power of the AC/DC inverter 5 reaches the lower limit value of -50 kW.

After time T1, when the output power of the first DC/DC converter 3 further decreases, the AC/DC inverter 5 cannot decrease the converted power from -50 kW, and the voltage VD of the DC power line 6 becomes the first voltage. Decrease from VD1. Then, at time T2, it reaches a fourth voltage VD4 (for example, 340 V) that is lower than the first voltage VD1. The fourth voltage VD4 is set to a value higher than the lowest DC voltage of the power supply facility 1. The minimum DC voltage is set to a value (eg, 320 V) higher than the maximum AC voltage value (eg, 220 2 V) at the AC output terminal of the AC/DC inverter 5 . When the voltage VD of the DC power line 6 becomes equal to or lower than the minimum DC voltage, the devices connected to the DC power line 6 (first DC/DC converter 3, power storage device 4, AC/DC inverter 5) all stop operating.

When the voltage VD of the DC power line 6 is equal to or lower than the fourth voltage VD4, the power storage device 4 stops the charge/discharge power control commanded by the power supply facility control unit 7 and executes the voltage control of the DC power line 6. At this time, in the present embodiment, the power storage device 4 uses the fourth voltage VD4 as a target value and performs voltage control with a discharge power less than the charge/discharge power upper limit value or a discharge current less than the charge/discharge current upper limit value. Further, voltage control is executed only when the SOC of the storage battery 41 is equal to or higher than the SOC lower limit commanded by the power supply facility control unit 7 . This operation secures the voltage necessary for the operation of the equipment connected to the DC power line 6 .

After time T2, the power storage device 4 continues voltage control with the fourth voltage as the target value due to an increase in discharge power.

After time T3, when the output power of the first DC/DC converter 3 increases, the power storage device 4 continues voltage control with the fourth voltage VD4 as the target value due to the decrease in discharge power. Then, when the output power of the first DC/DC converter 3 further increases, the voltage VD of the DC power line 6 becomes equal to or higher than the fourth voltage VD4 at time T4. At this time, the power storage device 4 terminates the voltage control of the DC power line 6 and restarts the charge/discharge power control instructed by the power supply equipment control unit 7 . After time T5, the voltage VD of the DC power line 6 is controlled to the first voltage VD1 by voltage control of the AC/DC inverter.

At time T when a new command is received from the power supply facility control unit 7, the voltage VD of the DC power line 6 is the first voltage VD1. At this time, the upper limit of the converted power of the AC/DC inverter 5 is updated to the minimum value of the rated power of the AC/DC inverter 5 and the upper limit of the converted power received from the power supply facility control unit 7 at time T. Also, the lower limit of the converted power of the AC/DC inverter 5 is updated to the maximum value of the rated power of the AC/DC inverter 5×(−1) and the lower limit of the converted power commanded from the power supply equipment control unit 7 .

The power storage device 4 operates according to the charge/discharge power command or the charge/discharge current command received from the power supply facility control unit 7 at time T. In addition, the charge/discharge power upper/lower limit value, the charge/discharge current upper/lower limit value, and the SOC upper/lower limit value are updated. The power after time T in FIG. 5 shows the case where the lower limit of the converted power of AC/DC inverter 5 is updated to −50 kW, and power storage device 4 discharges with the new charge/discharge power command value of −50 kW.

FIG. 6 shows control example 5 of the power of each part and the voltage VD of the DC power line when the present invention is applied. Since the process up to time T3 is the same as control case 4 shown in FIG. 5, the description is omitted. In FIG. 6, at time T, first DC/DC converter 3 executes MPPT control, and power storage device 4 controls voltage VD of DC power line 6 to a fourth voltage. In this embodiment, it is assumed that the power storage device 4 is operating with a discharge power of -55 kW (charge power of 55 kW).

AC/DC inverter 5 and power storage device 4 receive a new command from power supply facility control unit 7 at time T when voltage VD of DC power line 6 is greater than or equal to fourth voltage VD4 and less than first voltage VD1 , the upper limit of the converted power of the AC/DC inverter 5 is the minimum of the rated power of the AC/DC inverter 5 and the upper limit of the converted power received from the power supply equipment control unit 7 at time T, as described in FIG. value. Also, the lower limit of the converted power of the AC/DC inverter 5 is updated to the maximum value of the rated power of the AC/DC inverter 5×(−1) and the lower limit of the converted power commanded from the power supply equipment control unit 7 .

The power storage device 4 updates the charge/discharge power upper/lower limit value, the charge/discharge current upper/lower limit value, and the SOC upper/lower limit value to the new values received from the power supply facility control unit 7 . In addition, the power storage device 4 stores the charge/discharge power command or charge/discharge current command (referred to as a command value in the present embodiment) received from the power supply facility control unit 7 at time T, and the actual charge/discharge power at time T or The charge/discharge current (referred to as the actual value in this embodiment) is compared with the power and current in the discharge direction as positive. Then, when the command value is larger than the actual value, power storage device 4 terminates voltage control of DC power line 6 and performs charge/discharge power control according to the command value. If the command value is smaller than the actual value, voltage control of the DC power line 6 is continued. However, the command value received at time T is retained and used as a command value from power supply equipment control unit 7 when power storage device 4 terminates voltage control of DC power line 6 and restarts charge/discharge power control.

In FIG. 6, the discharge power of the power storage device 4 immediately before time T is -55 kW. At time T, when the power storage device 4 receives a charge/discharge power command of -40 kW from the power supply facility control unit 7, the command value is -40 kW, which is larger than the actual value of -55 kW. After completing the voltage control in step 6, discharge power control is performed according to the command value of -40 kW. At this time, the voltage VD of the DC power line 6 is controlled to the first voltage VD1 by voltage control of the AC/DC inverter.

FIG. 7 shows another configuration example of the power supply facility according to the first embodiment of the present invention. In FIG. 7 , an electric vehicle connector 611 is installed on the DC power line 6 . Then, the electric vehicle 11 is connected to the DC power line 6 via the electric vehicle connecting portion 611 . The electric vehicle connecting part 611 is a cable connector branched from the DC power line 6 and is an electrical contact between the electric vehicle 11 and the DC power line 6 . The electric vehicle 11 is, for example, an electric vehicle, an electric agricultural machine, a drone, or the like, and is not always provided in the power supply facility 1 . The electric vehicle 11 has a storage battery 41 and a DC/DC converter 42, and can charge the storage battery 41 by controlling the charging power by itself by DC power supply. Also, the electric power stored in the storage battery 41 can be discharged by direct current through the control of the DC/DC converter 42 .

The electric power supply facility 7 can issue charge/discharge power commands or charge/discharge current commands, charge/discharge current upper/lower limits, and SOC upper/lower limits to the electric vehicle 11. The configuration example shown in FIG. 1 and FIGS. can operate in the same manner as the power supply facility power and DC power line voltage example shown in .

In FIG. 7, the electric vehicle 11 may have a structure that does not have the DC/DC converter 42. In this case, the DC/DC converter 42 is separately provided externally. good too.

FIG. 8 shows still another configuration example of the power supply facility according to Embodiment 1 of the present invention, which is a connection example when the electric vehicle 11 does not have the DC/DC converter 42 . In FIG. 8 , one end of the DC/DC converter 42 is connected to the DC power line 6 , and the other end of the DC/DC converter 42 is provided with a motor-driven vehicle connection section 611 . Then, the electric vehicle 12 is connected to the DC power line 6 via the DC/DC converter 42 and the electric vehicle connection section 611 . The electric vehicle connection unit 611 is a cable connector for supplying the output of the DC/DC converter 42 to the electric vehicle 12 . The electric vehicle 12 is, for example, an electric vehicle, an electric agricultural machine, a drone, or the like, and is not always provided in the power supply facility 1 . The electric vehicle 12 has a storage battery 41 , and charges and discharges the storage battery 41 under charge/discharge power control of the DC/DC converter 42 . The configuration shown in FIG. 8 can also operate in the same manner as the configuration shown in FIG.

FIG. 9 shows a configuration example of a power supply facility according to Embodiment 2 of the present invention. In this embodiment, the power supply facility 1 includes a received power measuring unit 12 in addition to the configuration shown in the first embodiment. Below, portions different from the first embodiment will be described.

This embodiment is applied to the power supply facility 1 and the load 10 interconnected to the AC power supply 9 on the condition that reverse power flow does not occur. In an interconnection that does not allow reverse power flow, a reverse power flow relay is installed at the power receiving point, and the circuit breaker is opened when a reverse power flow occurs. When supplying power to the load 10 with the power generated by the solar cell 2 and the discharged power of the storage device 4, the occurrence of reverse power flow must be prevented so that the circuit breaker is not opened.

Since the conversion power upper limit command to the AC/DC inverter 5 and the charging/discharging power command or charging/discharging current command to the power storage device 4 by the power supply facility 7 are performed at a constant cycle (for example, 1 minute), a constant cycle or more Reverse power flow can be prevented when the power consumption of the load 10, which requires time, gradually decreases. However, if the power consumption of the load 10 suddenly decreases within a period of less than a certain period, the update of the command value of the power supply facility 7 will not be in time, causing a reverse power flow and opening the circuit breaker. If the command cycle of the power supply facility 7 is set to a short period (for example, 0.1 second) in order to prevent reverse power flow, the facility cost of the power supply facility 7 will increase.

Therefore, in this embodiment, the received power measurement unit 12 measures the power at the power receiving point 91 of the AC power supply 9, and issues an AC output stop command 13 to the AC/DC inverter 5 while the received power is equal to or less than a predetermined value (for example, 1 kW). Send. When the AC/DC inverter 5 receives the AC output stop command 13, it sets the upper limit of the converted power to 0 kW from the time of reception until it receives the new converted power upper limit value command of the power supply facility 7. After the time when the new conversion power upper limit command for the power supply facility 7 is received, the upper limit of the conversion power of the AC/DC inverter 5 is the rated power of the AC/DC inverter 5 and the conversion commanded by the power supply facility control unit 7. It is set to the minimum power cap value.

FIG. 10 shows an example of controlling the power of each part and the voltage VD of the DC power line when the second embodiment of the present invention is applied. In this embodiment, as in the first embodiment, the converted power P5 of the AC/DC inverter 5 is positive when output to the AC side and negative when input (power reception) from the AC side. Also, the charge/discharge power P4 of the power storage device 4 is positive when discharged and negative when charged. Assume that the output P3 of the first DC/DC converter 3 is positive.

Let 0 be the time when the power storage device 4 and the AC/DC inverter 5 receive the command from the power supply facility control unit 7 . The power supply equipment control unit 7 transmits a command at a fixed cycle T. Therefore, it is time T that power storage device 4 and AC/DC inverter 5 next receive a command.

At time 0, the upper limit of the converted power P5 of the AC/DC inverter 5 is set to 50 kW by a command from the power supply facility control unit 7. The power storage device 4 has an upper limit of charge/discharge power of 30 kW and a lower limit of charge/discharge power of -30 kW, and discharges at 30 kW to supply power to the load 10 . Also, at time 0, the output of the first DC/DC converter 3 is assumed to be constant at 10 kW for simplicity. At this time, the sum of the output P3 of the first DC/DC converter 3 and the discharged power P4 of the power storage device 4 is 40 kW, which is less than the upper limit of the converted power P5 of the AC/DC inverter 5. is power conversion of 40 kW, the voltage VD of the DC power line 6 can be controlled to the first voltage VD1.

When the AC/DC inverter 5 receives the AC output stop command 13 at time T1, the upper limit of the converted power P5 of the AC/DC inverter 5 is updated to 0 kW. Therefore, the converted power of the AC/DC inverter 5 was 40 kW until time T1, but becomes 0 kW after time T1. Then, the voltage VD of the DC power line 6 rises, and the voltage VD of the DC power line 6 exceeds the second voltage VD2 at time T2.

When the voltage VD of the DC power line 6 is equal to or higher than the second voltage VD2, the power storage device 4 stops charging/discharging power control instructed by the power supply facility control unit 7 and executes voltage control of the DC power line 6. At this time, in the present embodiment, the power storage device 4 performs voltage control with the second voltage VD2 as the target value. In addition, the power storage device 4 performs voltage control with a discharge power equal to or higher than the charge/discharge power lower limit commanded by the power supply facility control unit 7 or a discharge current equal to or higher than the charge/discharge current lower limit commanded. In this embodiment, it is assumed that -30 kW is commanded as the charge/discharge power lower limit.

At time T, the upper limit of the converted power P5 of the AC/DC inverter 5 is updated to the minimum value of the rated power of the AC/DC inverter 5 and the upper limit of the converted power received from the power supply equipment control unit 7. In this embodiment, it is assumed that the power is updated to 30 kW.

The power storage device 4 updates the charge/discharge power upper/lower limit value, the charge/discharge current upper/lower limit value, or the SOC upper/lower limit value to the new upper/lower limit value received from the power supply facility control unit 7 .

At time T, the voltage VD of the DC power line 6 is greater than or equal to the second voltage VD2 and less than the third voltage VD3. The discharge current command (referred to as the command value in this embodiment) and the actual charge/discharge power or charge/discharge current at time T (referred to as the actual value in this embodiment) are the power and current in the discharge direction. Compare as positive.

Then, if the command value is smaller than the actual value, the power storage device 4 terminates the voltage control of the DC power line 6 and performs charge/discharge power control according to the command value. If the command value is greater than the actual value, voltage control of the DC power line 6 is continued. In this embodiment, it is assumed that a command value of 10 kW, which is larger than the actual value, is received. At this time, power storage device 4 continues voltage control of DC power line 6 .

After time T, the AC/DC inverter 5 starts controlling the voltage VD of the DC power line 6 to the first voltage VD1 with the converted power of 30 kW as the upper limit. On the other hand, since the power storage device 4 continues to control the voltage of the DC power line 6 , the discharge power is increased in accordance with the increase in the converted power of the AC/DC inverter 5 . At time T3, when the charge/discharge power of the power storage device 4 reaches the charge/discharge power of 10 kW commanded by the power supply facility control unit 7 at time T, the power storage device 4 ends the voltage control of the DC power line 6 and supplies power. Charge/discharge power control is performed at 10 kW commanded from the facility control unit 7 . The voltage VD of the DC power line 6 is controlled to the first voltage VD1 by voltage control of the AC/DC inverter.

Note that in this embodiment, the power storage device 4 can be replaced with the configuration of the electric vehicle connection unit 611 and the electric vehicle 11 shown in FIG. 7 of the first embodiment.

FIG. 11 shows a configuration example of a power supply facility according to Embodiment 3 of the present invention. In this embodiment, a power storage device 4A is connected to the DC power line 6 in addition to the power storage device 4. FIG. Like the power storage device 4, the power storage device 4A includes a storage battery 41A and a DC/DC converter 42A, and can charge and discharge the storage battery 4A under the control of the DC/DC converter 42A. Below, portions different from the first and second embodiments will be described.

In this embodiment, when the voltage VD of the DC power line 6 becomes equal to or higher than the second voltage VD2 or less than the fourth voltage VD4, if the power storage device 4 and the power storage device 4A independently control the voltage of the DC power line 6, Each voltage control interferes, and there exists a possibility that the voltage VD of the DC power line 6 may not be stabilized. Therefore, when two or more power storage devices are connected to the DC power line 6, voltage control of the DC power line 6 by the power storage devices is performed in one of the following two ways.

The first is droop control. The power supply facility control unit 7 transmits a charge/discharge power command or a charge/discharge current command, a charge/discharge power upper/lower limit value command or a charge/discharge current upper/lower limit value command, and an SOC upper/lower limit value command to the power storage device 4 and the power storage device 4A. A droop gain is set in advance for the power storage device 4 and the power storage device 4A. When the voltage VD of the DC power line 6 is equal to or higher than the second voltage VD2 or the fourth voltage VD4 or lower, the power storage device 4 and the power storage device 4A change the voltage VD of the DC power line 6 to the second voltage VD2 or Control to the fourth voltage VD4.

Note that the droop gain may be sequentially transmitted from the power supply facility control unit 7. That is, the power supply facility control unit 7 sends a charge/discharge power command or a charge/discharge current command to the power storage device 4 or the power storage device 4A, a charge/discharge power upper/lower limit value command or a charge/discharge current upper/lower limit value command, an SOC upper/lower limit value command, Send droop gain. Power storage device 4 and power storage device 4A perform droop control according to the droop gain received from power supply facility control unit 7 when voltage VD of DC power line 6 is equal to or higher than second voltage VD2 or equal to or lower than fourth voltage VD4. and controls the voltage VD of the DC power line 6 to the second voltage VD2 or the fourth voltage VD4.

However, when the charging/discharging power or charging/discharging current determined according to the droop gain takes a value outside the range of the charging/discharging power upper/lower limit value or the charging/discharging current upper/lower limit value commanded from the power supply facility control unit 7, Power storage device 4 and power storage device 4A perform charging and discharging at the commanded upper and lower limits of charge/discharge power or upper and lower limits of charge/discharge current. When the SOC of the storage battery 41 or the storage battery 41A reaches the commanded SOC upper limit value, the lower limit value of the discharge power is set to 0 kW and charging is not performed, and when the commanded SOC lower limit value is reached, the discharge power upper limit value is set to 0 kW and no discharge is performed.

The second method is to set the voltage control switching priority for the power storage device. In this method, the power storage device stops the charge/discharge power control commanded by the power supply facility control unit 7, and the second voltage DV2 and the fourth voltage DV4, which are the thresholds for executing the voltage control of the DC power line 6, are changed to the DC It is set for each power storage device connected to the power line 6 .

In this embodiment, the power storage device 4 stops charge/discharge power control commanded by the power supply facility control unit 7 at the second voltage VD2 and the fourth voltage VD4, and executes voltage control of the DC power line 6. Further, power storage device 4A stops charge/discharge power control instructed by power supply facility control unit 7 at second voltage VD2A and fourth voltage VD4A, and executes voltage control of DC power line 6. FIG.

The magnitude relationship between the second voltage VD2 and the second voltage VD2A and the magnitude relationship between the fourth voltage VD4 and the fourth voltage VD4A are independently determined, and the voltage control switching priority appears in this magnitude relationship. Here, the maximum values of the second voltage VD2 and the second voltage VD2A are set below the third voltage, and the minimum values of the second voltage VD2 and the second voltage VD2A are set above the first voltage. Further, the maximum values of the fourth voltage VD4 and the fourth voltage VD4A are set below the first voltage, and the minimum values of the fourth voltage VD4 and the fourth voltage VD4A are set above the minimum DC voltage.

The second voltage VD2, the second voltage VD2A, the fourth voltage VD4, and the fourth voltage VD4A are commands from the power supply equipment control unit 7, the power storage device 4, and the power supply equipment control unit 7 of the power storage device 4A. , power storage device 4 or power storage device 4A itself. In the present embodiment, it is assumed that the voltage is determined by a command from the power supply facility control unit 7. First voltage VD1<second voltage VD2<second voltage VD2A<third voltage VD3, first voltage VD1 >fourth voltage VD4>fourth voltage VD4A>lowest DC voltage.

FIG. 12 shows an example of controlling the power of each part and the voltage VD of the DC power line when the third embodiment of the present invention is applied. In this figure, the time at which power storage devices 4 and 4A and AC/DC inverter 5 receive a command from power supply facility control unit 7 is defined as zero. The power supply equipment control unit 7 transmits a command at a fixed cycle T. Therefore, it is time T that power storage devices 4, 4A and AC/DC inverter 5 next receive a command.

At time 0, the upper limit of the converted power P5 of the AC/DC inverter 5 is set to 50 kW by a command from the power supply facility control unit 7. The power storage device 4 and the power storage device 4A are set to have a charge/discharge power upper limit value of 10 kW and a charge/discharge power lower limit value of -20 kW, and are discharged at 10 kW to supply power to the load 10 . Also, at time 0, the output of the first DC/DC converter 3 is assumed to be 20 kW. At this time, the sum of the output of the first DC/DC converter 3 and the discharge power of the power storage device 4 and the power storage device 4A is 40 kW, which is less than the upper limit of the converted power P5 of the AC/DC inverter 5. The inverter 5 can control the voltage VD of the DC power line 6 to the first voltage VD1 by converting the power by 40 kW.

From time 0 to time T1, when the output power P3 of the first DC/DC converter 3 increases due to fluctuations in solar radiation, the AC/DC inverter 5 increases the converted power P5 to bring the voltage VD of the DC power line 6 to the first level. is controlled to VD1. At time T1, the output power P3 of the first DC/DC converter 3 becomes 30 kW, and the converted power P5 of the AC/DC inverter 5 reaches the upper limit value of 50 kW.

After time T1, when the output power of the first DC/DC converter 3 further increases, the AC/DC inverter 5 cannot increase the converted power P5 from 50 kW, and the voltage VD of the DC power line 6 becomes the first voltage. Rise from VD1. Then, at time T2, it reaches a second voltage VD2 (for example, 365 V) that is higher than the first voltage VD1.

When the voltage VD of the DC power line 6 is equal to or higher than the second voltage VD2, the power storage device 4 stops charging/discharging power control instructed by the power supply facility control unit 7 and executes voltage control of the DC power line 6. At this time, in the present embodiment, the power storage device 4 performs voltage control with the second voltage VD2 as the target value. In addition, the power storage device 4 performs voltage control with a discharge power equal to or higher than the charge/discharge power lower limit commanded by the power supply facility control unit 7 or a discharge current equal to or higher than the charge/discharge current lower limit commanded. In this embodiment, -20 kW is commanded as the charge/discharge power lower limit.

On the other hand, at this time, the power storage device 4A continues the charge/discharge power control commanded by the power supply facility control unit 7. After time T2, power storage device 4 executes voltage control with second voltage VD2 as a target value due to a decrease in discharge power.

At time T3, the discharged power of the power storage device 4 reaches -20 kW. After time T3, even if the output power P3 of the first DC/DC converter 3 further increases, the power storage device 4 cannot increase the charging power. It further rises and reaches a second voltage VD2A (for example, 375 V) higher than the second voltage VD2 at time T4.

When the voltage VD of the DC power line 6 is equal to or higher than the second voltage VD2A, the power storage device 4A stops charging/discharging power control instructed by the power supply facility control unit 7 and executes voltage control of the DC power line 6. At this time, in this embodiment, the power storage device 4A performs voltage control with the second voltage VD2A as the target value. Further, the power storage device 4A performs voltage control with a discharge power equal to or higher than the charge/discharge power lower limit commanded from the power supply facility control unit 7 or a discharge current equal to or higher than the charge/discharge current lower limit commanded. In this embodiment, -20 kW is commanded as the charge/discharge power lower limit.

After time T4, the power storage device 4A executes voltage control with the second voltage VD2A as the target value due to the decrease in the discharge power. At this time, when the solar radiation decreases and the power generated by the solar cell 2 decreases, the voltage VD of the DC power line 6 becomes less than the second voltage VD2A at time T5. At this time, the power storage device 4</b>A ends the voltage control of the DC power line 6 and restarts the charge/discharge power control instructed by the power supply facility control section 7 . Then, the voltage VD of the DC power line 6 is controlled to the second voltage VD2 by voltage control of the power storage device 4 .

Similarly, after time T5, when the solar radiation decreases and the power generated by the solar cell 2 decreases, the voltage VD of the DC power line 6 becomes less than the second voltage VD2 at time T6. At this time, the power storage device 4 terminates the voltage control of the DC power line 6 and restarts the charge/discharge power control instructed by the power supply equipment control unit 7 . The voltage VD of the DC power line 6 is controlled to the first voltage VD1 by voltage control of the AC/DC inverter 5 .

At time T when a new command is received from the power supply facility control unit 7, the voltage VD of the DC power line 6 is the first voltage VD1. At this time, the upper limit of the converted power P5 of the AC/DC inverter 5 is updated to the minimum value of the rated power P5 of the AC/DC inverter 5 and the upper limit of the converted power received from the power supply facility control unit 7 at time T. . Also, the lower limit of the converted power P5 of the AC/DC inverter 5 is the maximum value of the rated power of the AC/DC inverter 5×(−1) and the lower limit of the converted power commanded from the power supply equipment control unit 7 . Power storage device 4 operates according to the charge/discharge power command or the charge/discharge current command received from power supply facility control unit 7 at time T. FIG. In addition, the charge/discharge power upper/lower limit value, the charge/discharge current upper/lower limit value, and the SOC upper/lower limit value are updated.

As described above, when voltage control switching priority is set for each power storage device in a configuration in which a plurality of power storage devices are connected to the DC power line 6, the second voltage in the first and second embodiments is set to the second voltage for each power storage device. 2 voltage VD2, the second voltage VD2A, . . . , the voltage VD of the DC power line 6 can be controlled.

Also, in a configuration in which three or more power storage devices are connected, voltage control switching priority can be set for a power storage device group that performs droop control and each power storage device that does not perform droop control.

For example, when power storage device 4, power storage device 4A, power storage device 4B, and power storage device 4C are connected to DC power line 6, power storage device 4 and power storage device 4A perform droop control, and power storage device 4B and power storage device 4C perform droop control. Can be set to never run. At this time, the voltages for starting droop control of power storage device 4 and power storage device 4A are set to second voltage VD2 and fourth voltage VD4, and power storage device 4B and power storage device 4C start voltage control of DC power line 6. The voltages are set to a second voltage VD2B and a fourth voltage VD4B, a second voltage VD2C and a fourth voltage VD4C, respectively.

The magnitude relationship between the second voltage VD2, the second voltage VD2B, and the second voltage VD2C and the magnitude relationship between the fourth voltage VD4, the fourth voltage VD4B, and the fourth voltage VD4C are independently arbitrary. can be set to However, the maximum values of the second voltage VD2, the second voltage VD2B, and the second voltage VD2C are less than the third voltage VD3, and the minimum values are set higher than the first voltage VD1. Further, the maximum values of the fourth voltage VD4, the fourth voltage VD4B, and the fourth voltage VD4C are less than the first voltage VD1, and the maximum values of the fourth voltage VD4, the fourth voltage VD4B, and the fourth voltage VD4C are The minimum value is set higher than the minimum DC voltage.

In this embodiment, the power storage device 4 and the power storage device 4A can be replaced with the configurations of the electric movable body connecting portion 611 and the electric movable body 11 shown in FIG. 7 of the first embodiment, respectively.

FIG. 13 shows a configuration example of a power supply facility according to Embodiment 4 of the present invention. In this embodiment, one end (primary side) of the second DC/DC converter 60 is connected to the first DC power line 61 to which the first DC/DC converter 3 and the AC/DC inverter 5 are connected. do. A second DC power line 62 is connected to the other end (secondary side) of the second DC/DC converter 60 .

That is, the second DC/DC converter 60 divides the DC power line 6 in the configuration example of the power supply facility in the first embodiment. The second DC/DC converter 60 is a bi-directional converter, and can charge the power storage device 4 with the power generated by the solar cell 2 or the power of the AC power supply 9 received via the AC/DC inverter 5. can be fed to the load 10 via the AC/DC inverter 5 .

Depending on the configuration of the solar cell 2, the output voltage of the first DC/DC converter 3 is high (eg, 1000 V). The first voltage, which is the control target value, is set to a high voltage (for example, 1000 V), and as a result, the withstand voltage of the power storage device 4 must be increased. However, by installing the second DC/DC converter 60 and stepping down the output voltage (primary side voltage) of the first DC/DC converter 3, it is possible to prevent the electric storage device 4 from increasing the breakdown voltage.

In addition, by making the second DC/DC converter 60 an insulated bidirectional converter, the first DC/DC converter 3 and the power storage device 4 can be insulated. As a result, for example, even if the second DC power line 62 deteriorates and the human body touches the exposed conductor portion, a current path from the solar battery 2 as the power source to the human body is not formed, so the first DC power line Electric shock can be prevented even if the DC converter 3 is a non-insulated type (for example, a boost chopper circuit).

In this embodiment, the second DC/DC converter 60 always controls the ratio between the primary side voltage and the secondary side voltage V2 to be a constant value N during operation. That is, (primary side voltage)=N×(secondary side voltage). Here, N=20/7. The rated power of second DC/DC converter 60 is equal to the rated power of DC/DC converter 42 of power storage device 4 .

By the voltage ratio constant control by the second DC/DC converter 60 described above, the voltage of the second DC power line 62 becomes the first voltage VD1 (350 V) and the second voltage VD2 (370 V) shown in the first embodiment. , the third voltage VD3 (390 V), and the fourth voltage VD4 (340 V), the primary side voltage of the second DC/DC converter 60, that is, the voltage of the first DC power line 61 is the first They are the voltage VD1' (1000 V), the second voltage VD2' (1057 V), the third voltage VD3' (1114 V), and the fourth voltage VD4' (971 V).

In this embodiment, the power storage device 4 operates in the same manner as in the first embodiment. That is, when the voltage value of the second DC power line 62 is equal to or higher than the second voltage that is higher than the first voltage, and is lower than the fourth voltage that is lower than the first voltage, the second voltage control of the DC power line 62 is performed.

The voltage control target value of the AC/DC inverter 5 is set to the first voltage VD1′, and the threshold voltage at which the first DC/DC converter 3 ends MPPT control and performs voltage control is set to the third voltage VD3′. do. When the AC/DC inverter 5 can control the voltage of the first DC power line 61 to the first voltage VD1', the voltage of the second DC power line 62 becomes the first voltage VD1.

As described in the first embodiment, the AC/DC inverter 5 cannot control the voltage of the first DC power line 61 to the first voltage VD1' due to the upper and lower limit values of the converted power, and the first voltage VD1' It may rise to the second voltage VD2' (1057V) or fall to the fourth voltage VD4' (971V). At this time, the voltage of the second DC power line 62 also rises or falls corresponding to the rise or fall of the voltage of the first DC power line 61 . Assuming that the voltage of the first DC power line 61 rises to the second voltage VD2′, the voltage of the second DC power line 62 then rises to the second voltage VD2, and the power storage device 4 is charged to the second DC power line. 62 voltage control is started. Even if the power storage device 4 executes voltage control, if the voltage of the second DC power line 62 rises and reaches the third voltage VD3, then the voltage of the first DC power line 61 reaches the third voltage It rises to VD3'. At this time, the first DC/DC converter 3 ends the MPPT control and controls the voltage of the first DC power line 61 .

As described above, the voltage control target value of the AC/DC inverter 5 is set to the first voltage VD1′, and the threshold voltage at which the first DC/DC converter 3 ends MPPT control and performs voltage control is set to the third voltage. By setting it to VD3′ and applying other controls and operations according to the first embodiment, the same effects as in the first embodiment can be obtained even in the configuration example of the power supply facility in the present embodiment. The same applies to the second and third embodiments.

FIG. 14 shows a configuration example of power supply equipment according to Embodiment 5 of the present invention. In this embodiment, the first DC/DC converter 3, the AC/DC inverter 5, and the power storage device 4 are connected to the first DC power line 61, which is the primary side of the second DC/DC converter 60. A power storage device 4A is connected to a second DC power line 62 on the secondary side of the second DC/DC converter 60 . That is, the power storage device is connected to each of the primary side and the secondary side of the second DC/DC converter 60 . The rated power of second DC/DC converter 60 is equal to the rated power of DC/DC converter 422 of power storage device 4A.

The second DC/DC converter 60 performs constant voltage ratio control (N=20/7) as in the fourth embodiment. That is, the voltage of the second DC power line 62 is the first voltage VD1 (350 V), the second voltage VD2 (370 V), the third voltage VD3 (390 V), and the fourth voltage VD4 shown in the third embodiment. (340 V), the second voltage VD2 (365 V), and the second voltage VD2A (375 V), the voltage of the first DC power line 61 is the first voltage VD1' (1000 V), the second voltage VD2 ' (1057 V), a third voltage VD3' (1114 V), a fourth voltage VD4' (971 V), a second voltage VD2' (1043 V), and a second voltage VD2A' (1071 V).

The voltage control target value of the AC/DC inverter 5 is set to the first voltage VD1′, and the threshold voltage at which the first DC/DC converter 3 ends MPPT control and performs voltage control is set to the third voltage VD3′. do. Further, the power storage device 4 suspends the charge/discharge power control commanded by the power supply facility control unit 7 and sets the threshold voltage at which the voltage control of the first DC power line 61 is executed to the second voltage VD2′ or the second voltage VD2 ', and the fourth voltage VD4'. Other controls and operations conform to those of the third embodiment, so that the same effects as those of the third embodiment can be obtained even in the configuration example of the power supply facility in the present embodiment.

DESCRIPTION OF SYMBOLS 1... Power supply facility, 2... Solar cell (renewable energy power supply), 3... First DC/DC converter, 4, 4A... Power storage device, 5... AC/DC inverter, 6... DC power line, 7... Power supply Equipment control unit 8 Distribution line 9 AC power supply 10 Load 12 Power receiving power system side 13 AC output stop command 60 Second DC/DC converter 61 First DC power line , 62 ... second DC power line

Claims

A first conversion device that is arranged between an AC power line and a DC power line and performs power conversion, a second conversion device that is arranged between the DC power line and a storage battery and performs power conversion, and can be regenerated with the DC power line A power supply facility including a third conversion device that is arranged between energy power sources and performs power conversion,
The first converter controls the voltage of the DC power line to a first voltage, and the second converter controls the voltage of the DC power line to the first voltage. First, when the voltage of the DC power line exceeds a second voltage set higher than the first voltage, the voltage of the DC power line is controlled to a second voltage.
The power supply facility according to claim 1,
The third converter is a third voltage in which the second converter cannot control the voltage of the DC power line to a second voltage and the voltage of the DC power line is set higher than the second voltage power supply equipment, wherein the voltage of the DC power line is controlled to a third voltage when the voltage exceeds .
The power supply facility according to claim 2,
The power supply characterized in that the third converter performs maximum power point tracking (MPPT) control on the generated power output from the renewable energy power supply when the voltage of the DC power line is equal to or lower than the third voltage. Facility.
The power supply facility according to any one of claims 1 to 3,
In the second conversion device, the first conversion device cannot control the voltage of the DC power line to a first voltage, and the voltage of the DC power line is set lower than the first voltage. A fourth voltage and controlling the voltage of the DC power line to a fourth voltage when the voltage falls below.
A first conversion device that is arranged between an AC power line and a DC power line and performs power conversion, a second conversion device that is arranged between the DC power line and a storage battery and performs power conversion, and can be regenerated with the DC power line Power supply facility control for giving control commands to a third conversion device arranged between energy power sources to perform power conversion, and to the first conversion device, the second conversion device, and the third conversion device and a power supply facility comprising:
The power supply facility control unit transmits a maximum power conversion capacity command as the control command to the first conversion device, and the first conversion device limits the power capacity specified by the maximum power conversion capacity command. as a power supply facility, wherein the voltage of the DC power line is controlled to a first voltage.
The power supply facility according to claim 5,
The power supply facility control unit transmits a charge/discharge power command or a charge/discharge current command as the control command to the second conversion device, and the second conversion device is such that the first conversion device is the DC power line When the voltage of the DC power line cannot be controlled to the first voltage, and the voltage of the DC power line exceeds the second voltage or falls below the fourth voltage lower than the first voltage, the charge/discharge power command or the A power supply facility characterized by controlling the voltage of the DC power line to the second voltage or the fourth voltage by excluding a charge/discharge current command.
The power supply facility according to claim 1,
The power supply facility includes a received power measurement unit, and the received power measurement unit transmits an output stop command to the first conversion device when the measured received power falls below a predetermined value,
The first conversion device controls the voltage of the DC power line to a first voltage before receiving the output stop command, and stops operation after receiving the output stop command,
The power supply facility, wherein the second converter controls the voltage of the DC power line to the second voltage when the voltage of the DC power line exceeds the second voltage.
The power supply facility according to claim 1,
The first conversion device and the third conversion device are connected to one end of the fourth conversion device by a first DC power line, and the other end of the fourth conversion device is the first DC power line Via connected to the second conversion device;
The fourth converter controls the ratio of the voltage of the first DC power line to the voltage of the second DC power line to a constant value,
The first converter controls the voltage of the first DC power line to a voltage value obtained by multiplying the first voltage by the constant value,
In the second conversion device, the first conversion device cannot control the voltage of the first DC power line to a voltage value obtained by multiplying the first voltage by the constant value, and the voltage of the second DC power line A power supply facility characterized by controlling the voltage of the second DC power line to the second voltage when the voltage exceeds the second voltage.
The power supply facility according to claim 8,
The third converter controls the voltage of the DC power line to the third voltage when the voltage of the first DC power line exceeds a voltage value obtained by multiplying the third voltage by the constant value. A power supply facility characterized by:
The power supply facility according to claim 9,
When the voltage of the first DC power line is equal to or lower than the voltage value obtained by multiplying the third voltage by the constant value, the third converter converts the generated power output from the renewable energy power source to the maximum power point A power supply facility characterized by follow-up (MPPT) control.
The power supply facility according to claim 8,
The fourth converter is characterized in that, when the voltage of the second DC power line falls below a fourth voltage lower than the first voltage, voltage control of the second DC power line is performed. power supply equipment.
The power supply facility according to claim 8,
a power storage device including a storage battery and a second conversion device for power conversion of the output of the storage battery is connected to the first DC power line and the second DC power line,
When the voltage of the first DC power line exceeds the voltage value obtained by multiplying the second voltage by the constant value, the power storage device connected to the first DC power line is connected to the first DC power line. A power supply facility characterized by implementing voltage control of
The power supply facility according to claim 12,
When the voltage of the first DC power line falls below a voltage value obtained by multiplying a fourth voltage lower than the first voltage by the constant value, the power storage device connected to the first DC power line , a power supply facility characterized by implementing voltage control of the first DC power line.
The power supply facility according to claim 1,
A power supply facility, wherein the storage battery is mounted on an electric vehicle.
The power supply facility according to claim 1,
A plurality of sets of power storage devices each including a storage battery and a second conversion device that converts the output of the storage battery into power are connected to the DC power line, and the power storage device stops the commanded charge/discharge power control and the DC power line. A power supply facility characterized in that a threshold value for executing voltage control of is set for each power storage device.
A first conversion device that is arranged between an AC power line and a DC power line and performs power conversion, a second conversion device that is arranged between the DC power line and a storage battery and performs power conversion, and can be regenerated with the DC power line A power supply facility including a third conversion device that is arranged between energy power sources and performs power conversion,
A power supply facility control unit that gives a control command to the first conversion device, the second conversion device, and the third conversion device, and the first conversion device, the second conversion device, and the third conversion device. 3, each of the converters is provided with a voltage adjusting unit that controls the voltage of the DC power line to a first voltage, a second voltage, and a third voltage, respectively, and the voltage of the DC power line is adjusted by the voltage adjusting unit A power supply facility characterized by controlling to any one of a first voltage, a second voltage, and a third voltage.
The power supply facility according to claim 16,
The power supply facility, wherein the power supply facility control section performs long-cycle control, and the voltage adjustment section performs short-cycle control.