WO2015136682A1

WO2015136682A1 - Electricity storage system

Info

Publication number: WO2015136682A1
Application number: PCT/JP2014/056815
Authority: WO
Inventors: 伸治今井; 啓坂部
Original assignee: 株式会社日立製作所
Priority date: 2014-03-14
Filing date: 2014-03-14
Publication date: 2015-09-17

Abstract

The purpose of the present invention is to provide an electricity storage system in which a plurality of power conversion devices are connected by a communication means having a daisy chain structure and electricity storage devices and the power conversion devices can be replaced without interrupting the communication means and stopping the system during the replacement. An electricity storage system of the present invention has a plurality of power supply units each having an electricity storage device and a power conversion device connected to the electricity storage device. Control signal terminals of the power conversion devices included in the power supply units are connected in a daisy chain structure through a communication line. A communication line bypass circuit corresponding to each of the power supply units is connected to the each of the power supply units in parallel. The communication line bypass circuit has a switch that, when the power supply unit corresponding to the communication line bypass circuit is disconnected, makes it possible to communicate with power supply units adjacent to the power supply unit.

Description

Power storage system

The present invention relates to a power storage system.

In recent years, there are concerns about global warming due to an increase in carbon dioxide emissions and the depletion of fossil fuels. As one means of reducing the dependence on fossil fuels, the introduction of renewable energy obtained from nature such as wind power and sunlight is in progress. One of the advantages is that renewable energy is not depleted. On the other hand, since renewable energy depends on weather conditions, there is a demerit that the amount of available energy is large. In the future, the introduction of power generators and facilities using renewable energy is expected to expand, and technology to reduce power fluctuations due to the above disadvantages is essential.

As one of the means for suppressing the above power fluctuation, a power storage system equipped with a storage battery is attracting attention. The power storage system includes a power storage device (power storage device) that discharges and stores power and a power conversion system that converts the power into a form that can be easily used. The power storage system stores power when the amount of power is surplus, and keeps the amount of power supplied from renewable energy substantially constant by discharging the shortage of power when the amount of power is insufficient.

The power conversion system plays an important role in enabling electric power entering and exiting the power storage device to be connected to the AC power supply system. Therefore, high efficiency of the power conversion system in the power storage system is desired. Moreover, cost reduction of the power conversion system is also desired.

For power storage devices, it is desirable to reduce storage battery costs, reduce running costs by extending the life of storage batteries, and improve maintainability when replacing power storage devices. Note that examples of the power storage device include a device mounted with a secondary battery, a device mounted with a capacitor, and a capacitor.

In a power storage system equipped with the power storage device and the power conversion system as described above, for example, Japanese Patent Laying-Open No. 2012-1000039 (Patent Document 1) discloses a method for realizing high-efficiency operation and cost reduction of the power conversion system. is there. In this publication, “<Problem> Power converter configuration that easily detects low-cost abnormalities such as inability to transmit from the control device of each single-phase power converter and communication failure due to disconnection or short circuit of the optical fiber cable. <Solution> A power converter comprising a plurality of cascaded single-phase power converters and a central control device for controlling the plurality of single-phase power converters, wherein the plurality of single-phase power converters Each power converter has a single-phase power converter control device, and the central control device and the plurality of single-phase power converter control devices are connected by communication means having a daisy chain structure, and the single-phase power converter control The apparatus transmits / receives a control signal via the communication means having the daisy chain structure, and transmits / receives a signal having a specific pattern that can be distinguished from the control signal frame in addition to the control signal frame. It is described as determining. "Communication abnormality due to discrepancies between the unreceived or received signal with the specific pattern signal of the specific pattern signal of the power converter controller (see Abstract).

Moreover, in the power storage system as described above, Japanese Patent Application Laid-Open No. 2012-253862 (Patent Document 2) is one that realizes replacement and replacement of a power storage device without stopping system operation. In this publication, “<Problem> It is an object to provide a power storage system in which a power storage unit can be replaced without stopping the system. <Solution> The above problem loads

power converters

4, 5, 6, 7. Electrically connected in series on the connection end side, and electrically connect any one of the

power storage devices

8, 9, 10, 11 to the power connection ends of the

power converters

4, 5, 6, 7 In the power storage system 1, power usage rate changing means for changing the ratio of the power usage rates of the

corresponding power converters

4, 5, 6, 7 corresponding to each of the

power converters

4, 5, 6, 7. It is set as a typical solution means for solving the above representative problem ”(see the summary).

Patent Document 1 includes a plurality of power converters connected in cascade (series connection) and a central control device that controls the plurality of power converters, and each of the plurality of power converters includes a power converter control device. The central control unit and the plurality of power conversion devices are connected by communication means (for example, optical fiber cable) having a daisy chain structure, and the power conversion device transmits and receives signals through the communication means having a daisy chain structure. The power converter is described.

By adopting this daisy chain structure communication means, the cost of the communication cable length and the withstand voltage element for communication can be greatly increased compared to providing communication means one-to-one with each power converter from the central controller. Can be reduced.

Further, according to Patent Document 2, it is possible to replace the power storage device and the power storage device without stopping the operation of the power storage system, and it is possible to improve the maintainability during system operation.

JP 2012-1000039 Gazette JP 2012-253862 A

However, in the inventions disclosed in Patent Document 1 and Patent Document 2 described above, in order to reduce the cost of control communication of the power conversion device, when a communication means having a daisy chain structure is employed, in the related art, a specific power storage device or When the power converter is removed and replaced, the communication line is interrupted, and there is a problem that the system cannot be controlled.

Therefore, in the present invention, in a power storage system in which a plurality of power conversion devices are connected by communication means having a daisy chain structure, the communication means is not shut off when the power storage device and the power conversion device are replaced and replaced, and non-stop replacement of the system is realized. The purpose is to provide a power storage system that can be used.

In order to solve the above problems, the power storage system 1 of the present invention includes a plurality of power supply units M1 to M7 having power storage devices E1 to E7 and power conversion devices 10 to 70 connected to the power storage devices E1 to E7. The control signal terminals 10s to 70s of the power conversion devices 10 to 70 included in the power supply units M1 to M7 are connected to each other in a daisy chain structure via the communication line 6, and the power supply units M1 to M7 are connected to the power supply units M1 to M7. The communication line bypass circuits B1 to B7 corresponding to M7 are connected in parallel, and the communication line bypass circuits B1 to B7 are connected to the power supply unit when the power supply units M1 to M7 corresponding to the communication line bypass circuits B1 to B7 are disconnected. It has a switch which enables communication with an adjacent power supply unit.

Further, in the power storage system 1 of the present invention, the AC side connection terminals 10a to 70a of the power converters 10 to 70 included in the power supply units M1 to M7 are connected in series via the AC power line 7, respectively, and the respective power supply units M1 To M7 are connected in parallel with power line bypass circuits R1 to R7 corresponding to the power supply units M1 to M7, and the power line bypass circuits R1 to R7 have power supply units corresponding to the power line bypass circuits R1 to R7. When disconnected, the power supply unit includes a switch that enables power transfer to and from a power supply unit adjacent to the power supply unit.

According to the present invention, in a power storage system in which a plurality of power conversion devices are connected by communication means having a daisy chain structure, the communication means is not shut off when the power storage device and the power conversion device are replaced and replaced, and non-stop replacement of the system is realized. An electricity storage system that can be used can be provided.

It is a schematic block diagram of the electrical storage system which becomes one Example of this invention. It is a block diagram which shows the outline of the power converter device 10 of FIG. 3 is a timing chart schematically showing the relationship between the switch operation in the switching circuit 11 shown in FIG. 2 and the voltage between the terminals of the AC side connection terminals. It is a block diagram which shows schematic structure of the control apparatus 13 described in FIG. It is a block diagram which shows schematic structure of the central control apparatus 3 described in FIG. It is a timing chart which shows the example of command voltage waveform for one cycle of the electrical storage system which becomes one example of the present invention, and the ON / OFF operation pattern of the power converter AC side connection terminal. It is the voltage waveform which synthesize | combined the alternating current side output voltage of each power converter device. It is the example of the flowchart which showed the procedure at the time of removing the power supply unit M1 described in FIG. FIG. 2 is a schematic diagram illustrating a configuration after removing a power supply unit M1 in the power storage system illustrated in FIG. 1. FIG. 10 is an example of a flowchart showing a control procedure for attaching the power supply unit M1 to the power storage system shown in FIG. 9; It is a figure which shows the electric power generation farm which becomes one Example of this invention.

Hereinafter, a first embodiment of the present invention will be described.
<< Application of Invention >>
In the embodiment described below, as shown in FIG. 11, the invention of the present application is used as a power storage system in a power generation system 100 using a renewable energy, for example, a wind power generation system 110 or a solar power generation system 120. A case where the present invention is applied to the installed power storage system 1 will be described as an example.

Although the power generation system 100 using renewable energy has an advantage that the load on the natural environment is small, the power generation capacity depends on the natural environment such as the weather, and the output to the power system 200 fluctuates. The power storage system 1 is provided for suppressing (relaxing) the output fluctuation of the power generation system 100. When the power output from the power generation system 100 to the power system 200 is in a shortage state with respect to the predetermined output power, the power storage system 1 is discharged, and the power shortage of the power generation system 100 is compensated. When the power output from the power generation system 100 to the power system 200 is in a surplus state with respect to the predetermined power, the power storage system 1 receives and charges the surplus power of the power generation system.

The power generation system 100, the power system 200, and the power storage system 1 are electrically connected by an AC power supply system 210, respectively, so that power can be exchanged.
<< Other application applications of the invention >>
The configuration of the embodiment described below can also be applied to a stationary power storage system that is installed as an uninterruptible power supply (backup power supply) such as a data center server system or communication facility. In addition, the configuration of the embodiment described below is a stationary device that is installed in a consumer, stores nighttime power, and releases the stored power in the daytime to level the power load. It can also be applied to power storage systems.

Further, the configuration of the embodiment described below is electrically connected in the middle of the transmission / distribution system, and is used as a countermeasure for fluctuations in power transmitted / distributed in the transmission / distribution system, a countermeasure for surplus power, a countermeasure for frequency, a countermeasure for reverse power flow, etc. It can also be applied to a stationary power storage system.

Furthermore, the configuration of the embodiment described below is also applied to a mobile power storage system that is installed in a mobile body and used as a drive power source for driving the mobile body or a drive power source for driving a load mounted on the mobile body. Applicable. As the moving body, a hybrid electric vehicle using an engine and a motor as a driving source of the vehicle and a pure electric vehicle using a motor as a sole driving source of the vehicle, that is, a land traveling vehicle (a passenger car, a truck such as a truck, Railway cars such as buses), railway cars such as hybrid trains that use a motor driven by the power generated by the diesel engine, and industrial vehicles such as construction machinery and forklift trucks. and so on.

Hereinafter, examples will be described with reference to the drawings. In this embodiment, an example of a power storage system 1 in which a plurality of power storage devices using secondary batteries are connected in series via a power conversion device will be described.
"overall structure"
FIG. 1 is a schematic diagram of the overall configuration of a power storage system 1 in the present embodiment. The power storage system 1 includes an AC side connection terminal 2, power supply units M1 to M7, power line bypass circuits R1 to R7, a central control device 3, a current measuring device 4, a voltage measuring device 5, a communication line 6, and a communication line bypass circuit B1 to B7, AC power line 7 is provided.

The power supply units M1 to M7 have the same configuration, and each unit includes one power conversion device 10 to 70 and one power storage device E1 to E7. In the present embodiment, a configuration in which seven power supply units are electrically connected in series is shown. However, any number of similar power supply units may be used as long as two or more similar power supply units are connected in series. Further, in this embodiment, it is assumed that the power storage devices mounted on the power supply unit are all seven secondary batteries, but different types of power storage devices may be mixed between the plurality of power supply units. . For example, among a plurality of power supply units, a power storage device mounted on one power supply unit may be configured with a capacitor, and a power storage device mounted on another power supply unit may be configured with a secondary battery.

≪Overview of power converters 10 to 70≫
The power converters 10 to 70 are converters having a function of converting DC power into AC power or, conversely, converting AC power into DC power. The power storage devices E1 to E7 are connected to the DC side connection terminals 10d to 70d of the power conversion devices 10 to 70, respectively.

The power conversion devices 10 to 70 convert the DC power output from the corresponding power storage devices E1 to E7 into AC power, and generate AC power at the AC side connection terminals 10a to 70a of the power conversion devices 10 to 70, respectively. Let On the contrary, the power conversion devices 10 to 70 convert the AC power supplied from the AC side connection terminals 10a to 70a into DC power and output the DC power to the corresponding power storage devices E1 to E7, respectively.

Further, as shown in FIG. 1, the AC side connection terminals 10a to 70a of the power conversion devices 10 to 70 are electrically connected in series with each other, and one end of the AC side connection terminal 10a of the power conversion device 10 and the power conversion device 70 are connected. One end of each AC side connection terminal 70 a is connected to the AC side connection terminal 2 of the power storage system 1.

Thus, by electrically connecting the AC side connection terminals 10a to 70a of the power conversion devices in series, the combined voltage of the input and output voltages of the AC side connection terminals 10a to 70a of the power conversion devices 10 to 70 is stored in the power storage system. 1 appears at the AC side connection terminal 2 as the entire input / output voltage.

The power line bypass circuits R1 to R7 are electrically connected in parallel with the power converters 10 to 70, respectively. The power line bypass circuits R1 to R7 may be any circuit that can cut off the current, such as a relay switch. Normally, the power line bypass circuits R1 to R7 are in a non-conductive state (off), but are used as a current bypass circuit when the power supply unit is replaced.

The control signal terminals 10s to 70s are communication line terminals used for communication of control signals for controlling the operation of the power converters 10 to 70. As shown in FIG. 1, the control signal terminals 10 s to 70 s and the control signal terminal 3 s of the central controller 3 are connected by a communication line 6 having a daisy chain structure.

The communication line bypass circuits B1 to B7 are provided in parallel with the power supply units M1 to M7, respectively, with respect to the communication line 6 having the daisy chain structure described above. The communication line bypass circuits B1 to B7 may use any switching element as long as it has a function of conducting and blocking communication signals. Normally, the communication line bypass circuits B1 to B7 are in the cut-off state (off), but are controlled to be in a conductive state as necessary, such as when the power supply unit is replaced.

Specific operations of the communication line bypass circuit and the power line bypass circuit will be described later.
<Description of power storage device>
The power storage devices E1 to E7 have secondary batteries mounted therein as power storage elements. Although not shown in detail, each of the power storage devices E1 to E7 is configured as a cell group in which a plurality of secondary battery cells are connected in series and a secondary battery module formed by connecting these cell groups in parallel. ing. As such a secondary battery cell, for example, a lithium ion secondary battery, a lead storage battery, or a nickel metal hydride battery can be used. Further, a capacitor can be used instead of the secondary battery. As such a capacitor, for example, an electric double layer capacitor or a lithium ion capacitor can be used.
<< Description of AC terminal 2 and energy transfer >>
Although not shown in FIG. 1, an AC power supply system 210 such as a power generation system is electrically connected to the outside of the AC side connection terminal 2 of the power storage system 1, and the power storage devices E1 to E7 and the AC power supply system 210 are connected to each other. Electric energy can be sent and received between the two.

That is, the power storage system 1 discharges the electric energy stored in the power storage devices E1 to E7 as DC power, converts the discharged DC power into AC power by the power conversion devices 10 to 70, and converts the AC power to AC power It is possible to output to the system side 210. Further, the power storage system 1 inputs AC power supplied from the AC power supply system 210 side or the power generation system 100 from the AC side connection terminal 2, and converts the input AC power into DC power by the power converters 10 to 70. Thus, it is possible to store this DC power as electric energy in each of the power storage devices E1 to E7.
<< Description of Central Controller 3 >>
An overview of the central control device 3 shown in FIG. 1 will be described. The role of the central controller 3 is to control the operation of the power supply units M1 to M7 so that the power storage system 1 and the AC power supply system 210 can be connected to each other to exchange power.

The central controller 3 calculates command values for controlling the operations of the power supply units M1 to M7 based on various information and control programs. When the central control device 3 calculates the command value, the central control device 3 relates to the information regarding the AC voltage of the AC power supply system 210 and the AC current flowing between the AC power supply system 210 and the AC side connection terminal 2 of the power storage system 1. Information, and input / output voltage information of each power storage device connected to the power conversion devices 10 to 70 are used.

The central controller 3 outputs the calculated command value from the control signal terminal 3s and transmits the signal to each of the power supply units M1 to M7 via the communication line 6.

As a result, in each of the connection pairs of power conversion devices 10 to 70 and power storage devices E1 to E7, the operation of each internal switching circuit of power conversion devices 10 to 70 (details will be described later using FIG. 2) is controlled. In addition, the electrical connection between the switching circuit and the plurality of storage batteries is controlled, and the power exchanged between the two is controlled so that the power storage system 1 and the AC power supply system are linked. The outline of the internal configuration of the central controller 3 will be described later.

The voltage measuring device 5 measures the AC voltage of the AC power supply system and outputs a signal related to the measured AC voltage to the central control device 3. The current measuring device 4 measures an alternating current flowing through the alternating current side connection terminal 2 of the power storage system 1 and outputs a signal related to the measured alternating current to the central control device 3.
<< Description of Power Converter 10 >>
FIG. 2 is a diagram showing a configuration of the power conversion device 10 mounted on the power supply unit M1. The power storage system 1 in the present embodiment also includes the power conversion devices 20 to 70 in addition to the power conversion device 10. However, since the power conversion devices 10 to 70 all have the same configuration, the power conversion device 10 will be described below. I will explain only.

The power converter 10 includes a switching circuit 11, a smoothing capacitor 12, a control device 13 that controls the switching circuit 11, and a voltage measuring device 14 that detects an input / output voltage of the power storage device E1. Furthermore, an AC side connection terminal 10a electrically connected to the switching circuit 11, a DC side connection terminal 10d electrically connected to the power storage device E1, and a control signal terminal 10s are provided.

The control device 13 controls the operation of the switching circuit 11 based on information transmitted from the central control device 3 via the communication line 6 and the control signal terminal 10s. The internal configuration of the switching circuit 11 and the control device 13 will be described later.

As shown in FIG. 1, the DC side connection terminal 10d is electrically connected to the power storage device E1, and the voltage appearing at both ends of the terminal is referred to as V _E1 . Although not shown, the voltages appearing at both ends of the DC side connection terminals of the power converters 20 to 70 are also referred to as V _E2 , V _E3 , V _E4 , V _E5 , V _E6, and V _E7 , respectively.

Also, it will be referred to a voltage appearing across the AC-side connection terminals 10a and V _10. Although not shown, the voltages appearing at both ends of the AC side connection terminals 20a to 70a of the power conversion devices 20 to 70 are referred to as V ₂₀ , V ₃₀ , V ₄₀ , V ₅₀ , V ₆₀ and V ₇₀ , respectively. << Description of Switching Circuit 11 >>
The switching circuit 11 shown in FIG. 2 will be described. The switching circuit 11 includes normally-off type MOSFET (Metal Oxide Field Effect Transistor) 111, 112, 113, and 114, which are semiconductor switching elements. And the switching circuit 11 comprises the single phase full bridge inverter circuit by these four switching elements. Specifically, the drain sides of the

MOSFETs

111 and 113 and the source sides of the

MOSFETs

112 and 114 are connected to the DC side connection terminal 10d, and the source side of the MOSFET 111 (the drain side of the MOSFET 112) and the source side of the MOSFET 113 (the drain side of the MOSFET 114) are AC. It is connected to the side connection terminal 10a.

In the MOSFET, a diode (body diode) is formed between the source and the drain due to the structure of the element. Therefore, as shown in FIG. 2, D111, D112, D113, and D114 are parasitic in the

MOSFETs

111, 112, 113, and 114 as body diodes, respectively.

Normally, when an inverter circuit is configured with a switching element, it is necessary to provide a feedback diode in parallel with the switching element as a path for bypassing the energy of the inductive load to the power supply side when the switching element through which the current flows is turned off. However, in this embodiment, since the body diodes D111 to D114 built in the MOSFET function as feedback diodes, it is not necessary to provide a diode separately from the MOSFET.

In this embodiment, an example using a MOSFET is described as a switching element. However, other switching elements such as an IGBT (Insulated Gate Bipolar Transistor) may be used. However, since the body diode described above is not built in the IGBT, when the IGBT is applied as a switching element, it is necessary to separately provide a feedback diode in parallel.
<Description of switch operation>
Figure 3 is a timing showing a relationship of the four switching elements (MOSFET 111 ~ 114) on-off operation and the AC side connection terminals 10a terminal voltage V ₁₀ of the power conversion apparatus 10 of the switching circuit 11 shown in FIG. 2 It is a chart. Note that the directions of the potentials V _E1 and V ₁₀ for explaining the present embodiment are the directions of the arrows shown in the vicinity of the DC side connection terminal 10d and the AC side connection terminal 10a shown in FIG. The direction of the arrow is defined as the plus direction.)

Note that the switching circuits incorporated in each of the power conversion devices 20 to 70 also operate on the same principle as the switching circuit 11 of the power conversion device 10 described below.

The four MOSFETs included in the switching circuit 11 are controlled such that the

MOSFETs

111 and 112 are paired and the

MOSFETs

113 and 114 are paired, and in principle, the ON and OFF are in a reverse relationship within the same pair.

For example, when a potential is applied to the DC side connection terminal 10d, if two switches in the same pair of the switching circuits 11 are turned on at the same time, a current that is large enough to cause an electrical short circuit and cause the switching element to fail. May flow. Therefore, in any case, control is not performed so that two switches in the same pair are simultaneously turned on. When two switches in the same pair are controlled to be turned off at the same time, the DC side connection terminal 10d and the AC side connection terminal 10a are electrically disconnected and no current flows.

When each switch is controlled as in the period <1> and the period <3> shown in the timing chart of FIG. 3, the switch functions so that the switching circuit 11 is short-circuited when viewed from the AC side connection terminal 10a. The potential difference between the terminals is zero.

When each switch is controlled as in the period <2> in the timing chart of FIG. 3, the potential difference applied to the DC side connection terminal 10d, that is, the input / output voltage V _E1 of the power storage device E1 appears at the AC side connection terminal 10a. . On the contrary, when each switch is controlled as in the period <4>, the positive and negative polarities are reversed, and the output voltage −V _E1 appears at the AC side connection terminal 10a.

Actually, due to the influence of the on-resistance of the MOSFET, a potential difference is generated in the switch element portion when a current flows through each switch. Therefore, even if the switch control as time <2> and duration <4> shown in FIG. 3 a timing chart, the terminal value and the DC-side connecting terminal 10d of the terminal voltage V ₁₀ of the AC-side connection terminals 10a The magnitudes of the values of the inter-voltage V _E1 are not necessarily equal. However, for the sake of simplification in this embodiment, the influence of the on-resistance of the MOSFET is considered to be sufficiently negligible in the following including FIG. 3, and if the switch control is performed as in the period <2> of the timing chart, V ₁₀ = V _E1 , and V ₁₀ = −V _E1 when switch-controlled as in period <4>. The functions of the other power converters 20 to 70 are the same as those of the power converter 10 described above.
<< Description of Control Device 13 >>
The control apparatus 13 mounted in the power converter device 10 is demonstrated using FIG. A device similar to the control device 13 described below is mounted in the power conversion devices 20 to 70 as well. The control device 13 includes a slave communication unit 131, a data holding unit 132, a switch control / drive unit 133, and a voltage determination unit 134.

The slave communication unit 131 receives a control signal transmitted from the master communication unit 34 (described later) of the central control device 3 via the communication line 6 and the control signal terminal 10s, and only data related to the control of the power conversion device 10 is received. The control signal required by the power conversion device 10 is transmitted to the data holding unit 132 after identification and extraction. At the same time, the slave communication unit 131 sends information such as the voltage value of the power storage device E1, the presence or absence of abnormality of the power storage device, and control signals required by the other power conversion devices 20 to 70 to the control signal terminal 10s and the communication. Transmission is output to the control device of another power supply unit and the master communication unit 34 (described later) of the central control device 3 via the line 6.

In addition to the slave communication unit 131, communication functions between a plurality of slave communication units mounted on other power supply units and the master communication unit 34 of the central control device 3 include CAN (Controller Area Network), I ² C (Inter Any system that satisfies the required functions, such as -Integrated Circuit (SPI) and System Packet Interface (SPI) may be used.

The data holding unit 132 stores the control signal transmitted from the master communication unit 34 of the central control device 3 and the voltage information of the power storage device E1. Of the stored data, the control signal is read when the switch control / drive unit 133 (described later) is operated.

The switch control / drive unit 133 controls the on / off state of each switch of the MOSFETs 111 to 114 of the switching circuit 11 based on the control signal stored in the data holding unit. The switch control / drive unit 133 is provided with a gate drive circuit (not shown) for generating the gate voltage of these switches for each switch in order to turn on and off the MOSFETs 111 to 114.

Voltage determination unit 134 receives input / output voltage V _E1 of power storage device E1 detected by voltage measurement device 14, and determines whether the voltage value falls within an assumed value range. If there is no abnormality, the voltage information is passed to the data holding unit 132. If it is determined that the voltage value of the power storage device E1 is abnormal, an abnormal signal is sent to the data holding unit 132, and the central control device 3 passes through the slave communication unit 131 and the control devices of the other power supply units M2 to M7. An abnormal signal is sent to.

<< Description of Central Controller 3 >>
FIG. 5 is a block diagram showing an outline of functions of the central control device 3. The central control device 3 includes a command voltage calculation unit 31, a carrier calculation unit 32, an ON / OFF pattern calculation unit 33, a master communication unit 34, a power supply unit replacement control unit 35, and a bypass circuit control unit 36 therein. Among these, the power supply unit replacement control unit 35 and the bypass circuit control unit 36 do not operate when the power storage system 1 is performing a normal operation, and operate when the power supply unit is removed and replaced.

The command voltage calculation part 31 calculates the voltage waveform which the electrical storage system 1 inputs / outputs based on the electric current and voltage information of the alternating current system obtained from the current measuring device 4 and the voltage measuring device 5 shown in FIG.

The carrier calculation unit 32 shown in FIG. 5 is configured based on the input / output voltage values V _E1 to V _E7 of the power storage devices E1 to E7 and the command voltage information calculated by the command voltage calculation unit 31. For example, the position of the voltage level assigned to each power converter is determined.

The input / output voltage value information of the power storage devices E1 to E7 is output from each control device in each power conversion device in addition to the control device 13 in the power conversion device 10 shown in FIG. The data is sent to the carrier calculation unit 32 via the master communication unit 34 of the device 3.

The ON / OFF pattern calculation unit 33 shown in FIG. 5 converts each power conversion based on the command voltage output from the command voltage calculation unit 31 and each information of the carrier of each power conversion device output from the carrier calculation unit 32. The operation pattern of the switching circuit in the apparatus, that is, the ON / OFF pattern of the AC side output of each power converter is calculated.

An example of the operation of the ON / OFF pattern calculation unit 33 in FIG. 5 will be described with reference to FIG. FIG. 6 shows an example of a timing chart of the command voltage for one cycle, the carriers (C1 to C7) of each power converter, and the ON / OFF pattern of the AC side output of each power converter.

The command voltage 1 indicated by the solid line waveform on the lower side of FIG. 6 is a voltage waveform to be input / output when the power storage system 1 exchanges power with the AC power supply system. A command voltage 2 indicated by a broken line is a voltage waveform having a phase opposite to that of the command voltage 1. Further, broken triangle waves C1 to C7 are carriers for the power converters 10 to 70, respectively.

In the example shown in FIG. 6, the assigned voltage levels are assigned as

power conversion devices

70, 60, 50, 40, 30, 20, and 10 in order from the bottom, but this order depends on the output voltage and charge state of the power storage device. May be changed as appropriate.

The ON / OFF pattern of the AC output of each power conversion device shown on the upper side of FIG. 6 will be described. The command voltage 1 and the command voltage 2 are compared in magnitude relationship with each of the carriers C1 to C7. When the carrier is smaller than the command voltage 1, the AC output of the power converter corresponding to the carrier is turned on in the positive direction (indicated as “ON (+)” in FIG. 6). This is an operation corresponding to the period <2> of the timing chart shown in FIG.

Further, when the carrier is smaller than the command voltage 2, the AC side output of the power converter corresponding to the carrier is turned ON in the negative direction (indicated as “ON (−)” in FIG. 6). This is an operation corresponding to the period <4> of the timing chart shown in FIG.

When the carrier is larger than the command voltage 1 and the command voltage 2, the AC side output of the corresponding power converter is controlled to be OFF. This corresponds to the period <1> or the period <3> in the timing chart shown in FIG. 3, and the inter-terminal voltage of the AC side connection terminal of the corresponding power converter is 0 volt.

As described above, the ON / OFF pattern of each AC side input / output of the power converters 10 to 70 is determined by comparing the command voltage with the carrier. FIG. 6 shows an example in which six power converters are sufficient because of the amplitude of the command voltage. For this reason, in the timing chart on the upper side of FIG. 6, the AC output of the power converter 10 is always OFF for one cycle.

FIG. 7 shows a composite voltage appearing at the AC side connection terminal 2 of the power storage system 1 when the operation pattern of each power conversion device calculated by the ON / OFF pattern calculation unit 33 shown in FIG. 5 is directly output to the power conversion device. The waveform pattern of V is shown. In FIG. 7, the solid line waveform is the command voltage 1, and the solid line rectangular waveform is the combined voltage.
<Procedure for replacing the power supply unit>
Next, a specific procedure for removing and replacing the power supply unit M1 as an example among the plurality of power supply units mounted on the power storage system 1 will be described with reference to FIGS. 5 and 8 to 10. As a premise for removing a specific power supply unit from the power storage system 1, the power storage system 1 can maintain the command voltage 1 even if the number of power supply units is reduced by the amount removed until the power supply unit is removed, replaced, or attached. Must be able to input and output. For example, in the waveform pattern of the command voltage 1 shown in FIG. 6, even if the AC output V ₁₀ of the power converter ₁₀ is always OFF for one cycle, the power converters 20 to 70 are interlocked. If the ON / OFF operation is performed, a voltage sufficient to input / output the command voltage 1 can be obtained. Therefore, the power storage system 1 can continue to operate even if there is no power conversion device as long as it is any one of the seven power conversion devices.

5 has a function of sending a power supply unit removal request signal to the power supply unit replacement control unit 35 of the central control device 3 when removing a specific power supply unit. The external device 37 also has a function of detecting the installation state of each power supply unit mounted on the power storage device 1 and transmitting the information to the power supply unit replacement control unit 35.

FIG. 8 is a flowchart showing a control procedure performed by the central controller 3 when the power supply unit M1 is removed from the power storage system 1.

In step S101, a request for replacement of the power supply unit M1 is issued from the external device 37, and when the power supply unit replacement control unit 35 receives the request, the process proceeds to step S102. As a trigger for the external device 37 to transmit the above request, for example, there is a method in which an operator manually operates. Alternatively, the system may be constructed such that the external device 37 automatically operates when the power supply unit M1 is unlocked.

In step S102, the power supply unit replacement control unit 35 sends a request to the ON / OFF pattern calculation unit 33 to make the output voltage of the power conversion device 10 of the power supply unit M1 zero. This is to ensure safety when removing the power supply unit M1. In response to this request, the ON / OFF pattern calculation unit 33 calculates and outputs an ON / OFF pattern so that both ends of the AC side connection terminal 10a of the power conversion device 10 are short-circuit controlled. At this time, the switching circuit 11 in the power converter 10 is controlled as in the period <1> or the period <3> shown in the timing chart of FIG.

The power supply unit replacement control unit 35 is notified from the ON / OFF pattern calculation unit 33 that the AC side output voltage of the power supply unit M1 to be replaced is controlled to be zero (the AC side connection terminal 10a is internally short-circuited). Then, a signal is sent to the bypass circuit control unit 36 to operate the power line bypass circuit R1.

In step S103, the bypass circuit control unit 36 controls (turns on) the power line bypass circuit R1. In step 104, the power supply unit replacement control unit 35 is controlled by the ON / OFF pattern calculation unit 33 so that all of the MOSFETs 111 to 114 of the switching circuit 11 (FIG. 2) in the power conversion device 10 are turned off. The When the switching circuit 11 is controlled in this way, the power supply unit M1 is electrically disconnected from the AC power line of the power storage system 1. At this time, since it is necessary to conduct the power line bypass circuit R1 while the switching circuit 11 is controlled to be OFF, communication between the control device 13 and the outside is maintained during the conduction process of the power line bypass circuit R1. There is a need. Therefore, the power bypass circuit R1 is turned on earlier than the communication line bypass circuit B1 described later.

In step 105, the bypass circuit control unit 36 controls (turns on) the communication line bypass circuit B1. At this time, the slave communication unit 131 of the control device 13 (FIG. 4) simultaneously cuts off communication with the outside. Finally, the power supply unit M1 is removed from the power storage system 1 in step S106.

FIG. 9 is a configuration diagram showing the power storage system 1 with the power supply unit M1 removed. However, the wiring for controlling the power line bypass circuits R1 to R7 and the communication line bypass circuits B1 to B7 from the central controller 3 is not shown. As shown in FIG. 9, since both the power line bypass circuit R1 and the communication line bypass circuit B1 are ON-controlled, the power line and the communication line are not cut off even without the power supply unit M1, and the power storage system 1 operates. Can continue.

Next, the procedure for attaching the power supply unit M1 to the power storage system 1 will be described with reference to the flowchart of FIG. When power supply unit M1 is removed, it is assumed that both power line bypass circuit R1 and communication line bypass circuit R1 are kept on.

In step S201 in FIG. 10, when the power supply unit M1 is set at a predetermined position (original position) of the power storage system 1, the external device 37 shown in FIG. 5 detects the set state of the power supply unit M1, and the power supply unit A connection request signal for the power supply unit M1 is sent to the exchange control unit 35. At this time, since the switching circuit 11 of the power supply unit M1 is composed of a normally-off type MOSFET, the DC side connection terminal 10d, the AC side connection terminal 10a, and the AC power line 7 are electrically disconnected. .

Next, in step S202, the power supply unit replacement control unit 35 issues a signal to the bypass circuit control unit 36 to open (turn off) the communication bypass circuit B1, and the bypass circuit control unit 36 that has received this signal The communication line bypass circuit B1 is controlled to be opened (off). At the same time, the slave communication unit 131 in the control device 13 of the power conversion device 10 returns to a state in which communication with other control devices and the central control device 3 is possible.

In step S203, the power supply unit replacement control unit 35 sends a command signal to the ON / OFF pattern calculation unit 33 so as to short-circuit control the AC side connection terminal 10a of the power conversion device 10. The ON / OFF pattern calculation unit 33 receives this signal and calculates an ON / OFF pattern so that both ends of the AC side connection terminal 10a of the power conversion device 10 are controlled to be short-circuited. At this time, the switching circuit 11 in the power converter 10 is controlled as in the period <1> or the period <3> shown in the timing chart of FIG. As described above, the step of short-circuiting the AC side connection terminal 10a after the communication bypass circuit is turned off first and the control device 13 is brought into a communicable state allows the potential difference applied to the AC side connection terminal 10a to be changed to the power line. Since the potential difference between both ends of the bypass circuit R1 is aligned, it is possible to prevent malfunction of each device due to abnormal current such as inrush current flowing in the power line when the power line bypass circuit R1 described later is shut off.

In step S204, the power supply unit 35 issues a signal to the bypass circuit control unit 36 to open (turn off) the power line bypass circuit B1, and the bypass circuit control unit 36 that has received the signal outputs the power line bypass circuit R1. Open control (off). At this time, the power supply unit M1 is installed at a predetermined position of the power storage system 1, and the power line and the communication line are returned to the state before the replacement.

In step S205, the control mode of the central controller 3 returns to the same operation as when seven power supply units are connected in series.

The above is an example of a method of replacing the power supply unit without stopping the system in the power storage system 1.

As described above, the power storage system 1 of the present invention includes a plurality of power supply units M1 to M7 having the power storage devices E1 to E7 and the power conversion devices 10 to 70 connected to the power storage devices E1 to E7. The control signal terminals 10s to 70s of the power converters 10 to 70 included in M1 to M7 are connected to each other in a daisy chain structure via the communication line 6, and the power supply units M1 to M7 are connected to the power supply units M1 to M7. Corresponding communication line bypass circuits B1 to B7 are connected in parallel, and the communication line bypass circuits B1 to B7 are adjacent to the power supply unit when the power supply units M1 to M7 corresponding to the communication line bypass circuits B1 to B7 are disconnected. A switch that enables communication with the power supply unit is provided. By adopting such a configuration, even when the cost is reduced by adopting a daisy chain structure, control can be performed without disconnecting the communication line when any of the power supply units M1 to M7 is removed and replaced. Is possible. Therefore, continuous driving in a non-stop state is possible during maintenance of the power storage system 1 or the like.

Further, in the power storage system 1 of the present invention, the AC side connection terminals 10a to 70a of the power converters 10 to 70 included in the power supply units M1 to M7 are connected in series via the AC power line 7, respectively, and the respective power supply units M1 To M7 are connected in parallel with power line bypass circuits R1 to R7 corresponding to the power supply units M1 to M7, and the power line bypass circuits R1 to R7 have power supply units corresponding to the power line bypass circuits R1 to R7. When disconnected, the power supply unit has a switch that enables power transfer to and from the power supply unit adjacent to the power supply unit. By adopting such a configuration, as described above, continuous driving in a non-stop state is possible during maintenance of the power storage system 1 or the like.

The power storage system 1 of the present invention includes a central control device 3 that controls the power supply units M1 to M7. The central control device 3 includes a power supply unit replacement control unit 35 and an ON / OFF pattern calculation unit 33. The unit replacement control unit 35 specifies a target power supply unit based on a signal from the outside, and the ON / OFF pattern calculation unit 33 selects a target power supply unit M1˜M based on a signal from the power supply unit replacement control unit 35. A signal for short-circuiting control of the M7 power converters 10 to 70 is calculated. With such a configuration, voltage fluctuations of the power supply units M1 to M7 are suppressed during replacement, noise due to connection is suppressed, and stable control to other power conversion devices is possible.

In the power storage system 1 of the present invention, the central control device 3 has the bypass circuit control unit 36, and the power supply unit replacement control unit 35 puts the power conversion devices 10 to 70 of the target power supply units M1 to M7 into a short circuit state. In this case, a bypass circuit operation signal is output to the bypass circuit control unit 36, and the bypass circuit control unit 36 receives the bypass circuit operation signal and then receives the power line bypass circuit corresponding to the target power supply units M1 to M7. Control is performed to turn off the switches R1 to R7. Thus, by shutting off the power conversion devices 10 to 70 of the power supply units M1 to M7 first, it is possible to suppress a sudden voltage fluctuation when the power line is shut off and prevent malfunction of other devices.

Further, in the power storage system 1 of the present invention, after the switches of the power line bypass circuits R1 to R7 corresponding to the power supply units M1 to M7 targeted by the bypass circuit control unit 36 are turned off, the target power supply units M1 to M1 Control is performed to turn on the switches of the communication line bypass circuits B1 to B7 corresponding to M7. Thus, by cutting off the power line first and then connecting the communication line, it is possible to suppress the influence of noise caused by the power line cutoff and prevent malfunction of each device.

The power storage system 1 of the present invention includes a central control device 3 that controls the power supply units M1 to M7. The central control device 3 includes a power supply unit replacement control unit 35 and a bypass circuit control unit 36 to control power supply unit replacement control. When the power supply units M1 to M7 are attached from the outside, the unit 35 identifies the attached power supply unit, and the bypass circuit control unit 36 determines the power supply attached based on the signal from the power supply unit replacement control unit 35. Control is performed to turn off the switches of the communication line bypass circuits B1 to B7 corresponding to the units M1 to M7. As described above, when the power conversion devices 10 to 70 are brought into a controllable state in advance, the power supply units M1 to M7 can be connected and used immediately. In addition, since the power converters 10 to 70 are in a controllable state before being connected to the power line 7, it is possible to prevent destruction of other devices due to malfunctions or the like.

Further, in the power storage system 1 of the present invention, the central controller 3 has an ON / OFF pattern calculation unit 33, and the ON / OFF pattern calculation unit 33 is attached based on a signal from the power supply unit replacement control unit 35. The power conversion devices 10 to 70 of the power supply units M1 to M7 are controlled to be short-circuited. By making the power supply units M1 to M7 communicable in this way, the power converters 10 to 70 are brought into a short-circuited state, whereby an inrush current when reconnecting the power supply units M1 to M7 to the power line 7 is achieved. Can be prevented.

Further, in the power storage system 1 of the present invention, the bypass circuit control unit 36 applies power to the attached power supply units M1 to M7 after the power converters 10 to 70 of the attached power supply units M1 to M7 are in a short circuit state. Control is performed to turn off the switch of the corresponding power line bypass circuit 36. In this way, once the power converters 10 to 70 are short-circuited and then the power supply units M1 to M7 are disconnected, the safety when the power supply units M1 to M7 are disconnected is improved.

As described above, according to the present invention, in a power storage system in which a plurality of power conversion devices are connected by communication means having a daisy chain structure, the communication means is not shut off when the power storage device and the power conversion device are replaced and replaced. A power storage system that can realize stop replacement can be provided.

1: Power storage system 2: AC side connection terminal 3: Central control device 3s: Control signal terminal 4: Current measurement device 5: Voltage detection device 6: Communication line 7: AC power line 31: Command voltage calculation unit 32: Carrier calculation unit 33: ON / OFF pattern calculation unit,
34: Master communication unit 35: Power supply unit replacement control unit 36: Bypass circuit control unit,
37: External device,
10 to 70: Power conversion devices 10a to 70a: AC side connection terminals 10d to 70d: DC side connection terminals 10s to 70s: Control signal terminal 11: Switching circuit 12: Smoothing capacitor 13: Control device 14: Voltage measurement device E1 to E7: Power storage devices M1 to M7: Power supply units R1 to R7: Power line bypass circuits B1 to B7: Communication line bypass circuits

111 to 114: MOSFET
D111 to D114: Body diode 131: Slave communication unit 132: Data holding unit 133: Switch control / drive unit 134: Voltage determination unit C1 to C7: Carrier

Claims

In a power storage system having a plurality of power supply units having a power storage device and a power conversion device connected to the power storage device,
The control signal terminal of the power converter included in the power supply unit is connected to the daisy chain structure via a communication line,
A communication line bypass circuit corresponding to the power supply unit is connected in parallel to each of the power supply units. When the power supply unit corresponding to the communication line bypass circuit is disconnected, the power supply unit A switch that enables communication with the power supply unit adjacent to
The AC side connection terminals of the power converters included in the power supply unit are connected in series via AC power lines, respectively.
Each of the power supply units has a power line bypass circuit corresponding to the power supply unit,
The power line bypass circuit includes a switch that allows power to be exchanged with a power supply unit adjacent to the power supply unit when the power supply unit corresponding to the power line bypass circuit is disconnected.
The power storage system according to claim 1,
A central control device for controlling the power supply unit;
The central control unit has a power supply unit replacement control unit and an ON / OFF pattern calculation unit,
The power supply unit replacement control unit identifies a target power supply unit based on an external signal,
The ON / OFF pattern calculation unit calculates a signal for performing short-circuit control on the power conversion device of the target power supply unit based on a signal from the power supply unit replacement control unit.
The power storage system according to claim 2,
The central control unit has a bypass circuit control unit,
The power supply unit replacement control unit outputs a bypass circuit operation signal to the bypass circuit control unit when the power conversion device of the target power supply unit is in a short circuit state,
The said bypass circuit control part performs the control which makes the switch of the electric power line bypass circuit corresponding to the said power supply unit made into an interruption | blocking state after receiving the said bypass circuit operation signal.
The power storage system according to claim 3,
The bypass circuit control unit controls the switch of the communication line bypass circuit corresponding to the target power supply unit to be energized after the switch of the power line bypass circuit corresponding to the target power supply unit is cut off. A power storage system characterized by
The power storage system according to claim 1,
A central control device for controlling the power supply unit;
The central control unit has a power supply unit replacement control unit and a bypass circuit control unit,
The power supply unit replacement control unit identifies the attached power supply unit when the power supply unit is attached from the outside,
The power storage system, wherein the bypass circuit control unit performs control to turn off a switch of a communication line bypass circuit corresponding to the attached power supply unit based on a signal from the power supply unit replacement control unit.
The power storage system according to claim 5,
The central control unit has an ON / OFF pattern calculation unit,
The ON / OFF pattern calculation unit controls the power conversion device of the attached power supply unit to be in a short circuit state based on a signal from the power supply unit replacement control unit.
The power storage system according to claim 6,
The bypass circuit control unit performs control to turn off a switch of the power line bypass circuit corresponding to the attached power supply unit after the power converter of the attached power supply unit is in a short circuit state. A featured power storage system.