WO2014141396A1

WO2014141396A1 - Power source device

Info

Publication number: WO2014141396A1
Application number: PCT/JP2013/056894
Authority: WO
Inventors: 伸治今井; 啓角谷; 寛岩澤
Original assignee: 株式会社日立製作所
Priority date: 2013-03-13
Filing date: 2013-03-13
Publication date: 2014-09-18

Abstract

Provided is a power source device that, as a power source device using a series multiple power conversion device and an electricity storage device, can reduce the storage battery cost compared to when all the same type of storage battery is used. The power source device has an AC-side connection terminal and a DC-side connection terminal to which the electricity storage device, which is capable of being charged with and discharging electrical power, is connected, is provided with a plurality of the power conversion devices, and can interconnect with an AC power supply system by electrically connecting, in series, each of the AC-side connection terminals of the plurality of power conversion devices. The power source device is characterized in that the plurality of power conversion devices are classified into at least two groups, the combination of cathode active material and anode active material in the electricity storage element embedded in the electricity storage device connected to the DC-side connection terminal of the power conversion devices configuring the groups is the same within the groups, and the combination of cathode active material and anode active material of the electricity storage element embedded in the electricity storage device differs between the groups.

Description

Power supply

The present invention relates to a power supply device.

増大 There are concerns about an increase in carbon dioxide emissions, which is considered to be a cause of global warming, and the depletion of fossil fuels. As one of the means to reduce the dependence on fossil fuels, the introduction of renewable energy obtained from nature such as wind power and sunlight is progressing. One of the advantages of renewable energy is that there is no fear of depletion, but it also has the disadvantage of large fluctuations in the amount of available energy because it depends on weather conditions. 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 supply system equipped with a storage battery is attracting attention. This power supply system is composed of 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 is easy for the user to use, and stores power when the amount of power is surplus In addition, the amount of power supplied from renewable energy is kept almost constant by releasing the shortage of power when there is a shortage.

The power conversion system plays an important role in enabling the power entering and exiting the power storage device to be linked to the AC power supply system. Therefore, in order to effectively use the obtained power, it is desired to increase the efficiency of the power conversion system in the power storage system. Examples of the power storage device include those equipped with a secondary battery and those equipped with a capacitor, which are desired to reduce the storage battery cost and the running cost by extending the life of the storage battery.

For example, Japanese Patent Application Laid-Open No. 2006-320103 (Patent Document 1) discloses a power supply system equipped with a storage battery as described above, which realizes high-efficiency operation.

In Patent Document 1, n (n) connected to a DC power supply circuit is provided in order to equalize the power consumption of a plurality of single-phase power converters without impairing the harmonic suppression effect and to ensure safe and stable operation. Is a series multiple power converter capable of outputting a maximum of 2n + 1 potentials or a maximum of 4n + 1 potentials by connecting AC output terminals of a single-phase power converter in series. The means for calculating the PWM signal synchronized with the voltage command for the serial multiple power converter, and the timing at which the PWM signal changes are interchanged between the n single-phase power converters, and the single-phase power converters A control device for a serial multiple power conversion device including means for equalizing voltage output periods is described.

Also, Patent Document 1 discloses a method of replacing the PWM signal every half cycle of the voltage command.

JP 2006-320103 A

However, in the serial multiple power conversion device described in Patent Document 1, it is assumed that the battery connected as the DC power source is configured as a system with the same type of battery module (power storage device) configured by the same type of storage battery. It is said. In this case, there is a possibility that an over-spec battery module exceeding the actually required charging capacity may be included in the plurality of battery modules, and the battery cost cannot be suppressed because it exceeds the actually required battery capacity. There is.

Therefore, the present invention provides a power supply device that can reduce the storage battery cost for a power supply device that uses a series multiple power conversion device and a power storage device, as compared with the case where all of the same type of storage battery is applied.

A plurality of power conversion devices each having a DC side connection terminal to which a power storage device capable of charging and discharging electric power is electrically connected, and an AC side connection terminal, each of the plurality of power conversion devices being connected to each AC side A power supply device that can be connected to an AC power supply system by electrically connecting terminals in series, wherein the plurality of power conversion devices are classified into at least two groups, and the power constituting the group The combination of the positive electrode active material and the negative electrode active material of the power storage element built in the power storage device connected to the DC side connection terminal of the conversion device is the same within the group, and the power storage element built in the power storage device A combination of the positive electrode active material and the negative electrode active material is different between the groups.

According to the present invention, it is possible to provide a power supply device that can reduce the storage battery cost for a power supply device that uses a serial multiple power conversion device and a power storage device, as compared to the case where the same type of storage battery is applied.

It is a schematic block diagram of the power supply device which concerns on one Example of this invention. It is a block diagram which shows schematic structure of the power converter device of FIG. 3 is a timing chart schematically showing the relationship between the switch operation in the switching circuit 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 described in FIG. It is a block diagram which shows schematic structure of the central control apparatus described in FIG. It is a timing chart which shows the example of the command voltage waveform of the power unit concerning 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 a bar graph which shows the comparison of the power consumption of each electrical storage apparatus before performing electric energy correction | amendment. It is a bar graph which shows the comparison of the electric energy consumption of each electrical storage apparatus after carrying out electric energy correction | amendment. It is an example of the timing chart which shows the alternating current side output pattern of the

power converters

10 and 20 before and after electric energy correction | amendment. It is a schematic diagram of the timing chart of the alternating current side output pattern of each power converter device after electric energy amendment, and its synthetic voltage. FIG. 10 is a bar graph showing a comparison of power consumption of each power storage device after power amount correction by a method different from the method shown in FIG. 9. FIG. FIG. 13 is a timing chart of an AC side output pattern of each power conversion device and a schematic diagram of the combined voltage when power amount correction is performed in the power amount distribution illustrated in FIG. 12.

Embodiments of the present invention will be described.

In the embodiments described below, the invention of the present application is applied to a stationary power storage system installed as a power storage system in a power generation farm using a renewable energy, for example, a solar power generation system or a wind power generation system. A case will be described as an example.

∙ Power generation systems using renewable energy have the advantage of less impact on the natural environment, but the power generation capacity depends on the natural environment such as the weather, and the output to the power system fluctuates. The stationary power storage system is provided for suppressing (relaxing) the output fluctuation of the power generation system. When the power output from the power generation system to the power system is in a shortage state with respect to the predetermined output power, the stationary power storage system is discharged to compensate for the power shortage of the power generation system. When the power output from the power generation system to the power system is in a surplus state with respect to the predetermined power, the stationary power storage system receives and charges the surplus power of the power generation system.

The configuration of the embodiment described below can also be applied to a stationary power storage system installed as an uninterruptible power supply (backup power supply) such as a data center server system or communication equipment. 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. Examples of moving objects include automobiles such as hybrid electric vehicles that use an engine and a motor as the drive source of the vehicle and pure electric vehicles that use the motor as the sole drive source of the vehicle, that is, land-based vehicles (cars such as passenger cars and trucks). Automobiles, buses and other shared vehicles), electric vehicles powered by diesel engines, railway vehicles such as hybrid trains using motors driven by the power generated by this power generation, industries such as construction machinery and forklift trucks There are vehicles.

[Example]
Hereinafter, examples will be described with reference to the drawings.

In this embodiment, an example of a power supply device 1 in which a plurality of power storage devices using capacitors and a power storage device using secondary batteries are connected in series via a power conversion device will be described.
<Overall configuration>
FIG. 1 is a schematic diagram of an overall configuration of a power supply device 1 according to the present embodiment. The power supply device 1 includes an AC side connection terminal 2,

power conversion devices

10, 20, 30, 40, 50, 60, power storage devices E1, E2, E3, E4, E5, E6, a central control device 3, a current measurement device 4, A voltage measuring device 5 is provided.
<Overview of power converters 10 to 60>
The power converters 10 to 60 are converters having a function of converting DC power into AC power or, conversely, converting AC power into DC power. Power storage devices E1 to E6 are connected correspondingly to DC side connection terminals 10d to 60d of power conversion devices 10 to 60, respectively.

Each power conversion device 10 to 60 converts the DC power output from the corresponding power storage device E1 to E6 into AC power, and generates this AC power at the AC side connection terminals 10a to 60a of each power conversion device. Conversely, the AC power supplied from the AC side connection terminals 10a to 60a of each power conversion device is converted into DC power and output to the corresponding power storage device.

Further, the AC side connection terminals 10a to 60a of the power conversion devices 10 to 60 are electrically connected in series as shown in the figure, and one end of the AC side connection terminal 10a of the power conversion device 10 and the AC side connection terminal of the power conversion device 60 are connected. One end of 60a is connected to AC side connection terminal 2 of power supply device 1, respectively.

In this way, by connecting the AC side connection terminals 10a to 60a of each power conversion device in series, the combined voltage of the input and output voltages of each AC side connection terminal of the power conversion devices 10 to 60 becomes the input of the entire power supply device 1. It appears at the AC side connection terminal 2 as an output voltage.
<Description of power storage device>
The power storage device E1 constitutes a capacitor module (not shown) in which a plurality of capacitors are mounted as power storage elements and a plurality of capacitor cells are connected in series. As such a capacitor cell, for example, an electric double layer capacitor or a lithium ion capacitor can be used.

Each of the power storage devices E2 to E6 has a secondary battery mounted therein as a power storage element. Although not shown in detail, each of the power storage devices E2 to E6 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 a plurality of these cell groups in parallel. Has been. 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.

Although not shown in FIG. 1, an AC power supply system such as a power generation system is electrically connected to the outside of the AC side connection terminal 2 of the power supply device 1, and between the power storage devices E1 to E6 and the AC power supply system. It is possible to send and receive electrical energy.

That is, the power supply device 1 discharges the electric energy stored in the power storage devices E1 to E6 as DC power, converts the discharged DC power into AC power by the power conversion devices 10 to 60, and converts the AC power to the AC power source. It is possible to output to the system side. Further, the power supply device 1 inputs AC power supplied from the AC power supply system side or the power generation system from the AC side connection terminal 2, and converts the input AC power into DC power by the power converters 10 to 60, This DC power can be stored in each of the power storage devices E1 to E6 as electric energy.

In the present embodiment, a configuration in which six connection pairs of the power conversion device and the power storage device are connected in series is shown, but any number of series may be used as long as the connection pairs are two or more in series. In the present embodiment, one power storage device (E1) among the six power storage devices is mounted on the capacitor cell, but the system may be configured with two or more power storage devices mounted on the capacitor cell.
<Description of Central Controller 3>
Next, an overview of the central control device 3 shown in FIG. 1 will be described. The role of the central control device 3 is to control the operation of the connected pair of the power conversion devices 10 to 60 and the power storage devices E1 to E6 so that the power supply device 1 and the AC power supply system can be linked to exchange power. It is.

The central control device 3 calculates a command value for controlling the operation of the connected pair of the power conversion devices 10 to 60 and the power storage devices E1 to E6 based on various information and control programs. At the time of this calculation, the central control device 3 includes information on the AC voltage of the AC power supply system, information on the AC current flowing between the AC power supply system and the AC side connection terminal 2 of the power supply device 1, and further the power conversion device 10. The input / output voltage information of each power storage device connected to ˜60 is used.

The central control device 3 transmits the calculated command value to each of the power conversion devices 10 to 60 using wireless or wired communication. As a result, in each of the connection pairs of power conversion devices 10 to 60 and power storage devices E1 to E6, the operation of each internal switching circuit of power conversion devices 10 to 60 (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 electric power exchanged between the two is controlled so that the power supply device 1 and the AC power supply system are linked. Detailed operations performed by 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 supply device 1 and outputs a signal related to the measured alternating current to the central control device 3.
<Description of internal configuration of power converter>
FIG. 2 is a diagram illustrating a configuration of the power conversion device 10 in the power supply device 1. The power supply device 1 in the present embodiment also includes power conversion devices 20 to 60, but since these power conversion devices all have the same configuration, only the power conversion device 10 will be described below as a representative.

The power conversion device 10 includes a switching circuit 11, a smoothing capacitor 12, a control device 13, a voltage measuring device 14 that detects an input / output voltage of the power storage device E <b> 1, and an AC-side connection terminal 10 a that is electrically connected to the switching circuit 11. And a DC side connection terminal 10d connected to the power storage device E1. The control device 13 controls the operation of the switching circuit 11 based on information from the central control device 3. The control device 13 and the switching circuit 11 will be described later.

The DC side connection terminal 10d is connected to the power storage device E1 as shown in FIG. 1, and the voltage appearing at both ends of this terminal is referred to as V _E1 . Although not shown, the voltages appearing at the DC side connection terminals of the power converters 20 to 60 are also referred to as V _E2 , V _E3 , V _E4 , V _E5, and V _E6 , respectively. Also, will be referred to as V ₁₀ in the following a voltage appearing across the AC-side connection terminal 10a. Similarly, each voltage of the AC side connection terminals of the power conversion devices 20 to 60 will be referred to as V ₂₀ , V ₃₀ , V ₄₀ , V ₅₀ and V ₆₀ , respectively.
<Description of switching circuit>
The switching circuit 11 of FIG. 2 will be described. The switching circuit 11 includes N-channel MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) 111, 112, 113, and 114 that are semiconductor switching elements, and a single-phase full-bridge inverter circuit is configured by these four switching elements. . Specifically, the drain sides of

MOSFETs

111 and 113 and the source sides of

MOSFETs

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

N-channel MOSFET has a diode structure between its source and 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, the body diodes D111 to D114 built in the N-channel MOSFET function as the feedback diodes, so that it is not necessary to provide a separate diode.

In this embodiment, the case where an N-channel MOSFET is used as the switching element has been described as an example. 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 the switching element, it is necessary to provide a feedback diode separately.
<Operation of switching circuit>
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 in FIG. Although not described here, each switching circuit incorporated in the power converters 20 to 60 also operates on the same principle as the switching circuit 11 of the power converter 10 described below.

The four MOSFETs of the switching circuit 11 are controlled so 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. If a potential is applied to the DC side connection terminal 10d, if two switches in the same pair are turned on at the same time, an electrical short circuit may occur, and a large current that may cause a failure of the switching element 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 switching circuit is configured such that the insides of both terminals are electrically connected when viewed from the outside of the AC side connection terminal 10a. 11 functions, the potential difference between the terminals becomes zero. Further, when each switch is controlled as in the period <2> of the timing chart, a 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 polarity is reversed, and -V _E1 appears at the AC side connection terminal 10a.

Actually, a potential difference is generated in the switch element portion when a current flows through each switch due to the on-resistance of the MOSFET. 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 magnitude of the value of the inter-voltage V _E1 is not necessarily equal. However, in this embodiment, for simplification, in the following including FIG. 3, it is assumed that the influence of the on-resistance of the MOSFET is sufficiently negligible, and if the switch control is performed as in the period <2> of the timing chart, V ₁₀ = If switch control is performed as in V _E1 and period <4>, V ₁₀ = −V _E1 . The same applies to the other power conversion devices 20-60.
<Description of Control Device 13>
Next, the control device 13 will be described with reference to FIG. The control device 13 includes a communication unit 131, a data holding unit 132, a switch control / drive unit 133, and a voltage determination unit 134.

The communication unit 131 has a role of receiving a command signal transmitted from the central control device 3 corresponding to the host, and transmitting and outputting voltage information of the power storage device E1 to the central control device 3. As a communication function between the communication unit 131 and the host, any function that satisfies the necessary functions such as CAN (Controller Area Network), I ² C (Inter-Integrated Circuit), and SPI (System Packet Interface) can be used. It doesn't matter.

The data holding unit 132 stores the control command and control data transmitted from the central control device 3, and further the voltage information of the power storage device E1. The stored data is read when the switch control / drive unit 133 described later is operated. The voltage information of the power storage device E1 is transmitted to the central control device 3 via the communication unit 131.

The switch control / drive unit 133 controls the on / off state of each switch of the MOSFETs 111 to 114 in the switching circuit 11 based on the control information 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. If it is determined that the voltage value is abnormal, an abnormal signal is sent to the data holding unit, and the abnormal signal is transmitted to the central control device 3 via the communication unit 131.
<Detailed explanation of overall operation and capacitor capacity adjustment>
FIG. 5 is a block diagram showing an outline of functions of the central controller 3 shown in FIG. 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 power amount correction calculation unit 34, an ON / OFF pattern update calculation unit 35, and a communication unit 36 therein.

The command voltage calculation unit 31 shown in FIG. 5 calculates a voltage waveform input / output by the power supply device 1 based on the current and voltage information of the AC system obtained from the current measurement device 4 and the voltage measurement device 5 shown in FIG. .

The carrier calculation unit 32 shown in FIG. 5 is for each power conversion device based on the input / output voltage values V _E1 to V _E6 of the power storage devices E1 to E6 and the command voltage information calculated by the command voltage calculation unit 31. Are calculated, and the position of the voltage level in charge of each power converter is determined. The input / output voltage value information of the power storage devices E1 to E6 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. It is sent to the carrier calculation unit 32 via the unit 36.

The ON / OFF pattern calculation unit 33 shown in FIG. 5 is based on the command voltage output from the command voltage calculation unit 31 and the carrier information of each power conversion device output from the carrier calculation unit 32. The operation pattern of the switching circuit 11 shown, that is, the ON / OFF pattern of the AC output of each power converter is calculated.

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 carrier 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 sine waveform at the lower side of FIG. 6 is a voltage waveform to be input / output when the power supply device 1 exchanges power with the AC power supply system. Moreover, the command voltage 2 shown by the broken line sine waveform is a voltage waveform having a phase opposite to that of the command voltage 1. Further, broken triangle waves C1 to C6 are carriers for the power converters 10 to 60, respectively.

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

power conversion devices

60, 50, 40, 30, 20, and 10 in order from the bottom, but this order is appropriately determined according to the output voltage and the state of charge of the power storage device. You can change it.

The ON / OFF pattern of the AC side output of each power converter shown in the upper part 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 C6. 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.

In addition, 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 voltage is larger than the command voltage 1 and the command voltage 2, the AC side output of the corresponding power converter is turned 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 60 is determined by comparing the command voltage with the carrier.

FIG. 7 shows a composite voltage appearing at the AC side connection terminal 2 of the power supply device 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. V waveform pattern is shown. The solid line waveform is the command voltage 1, and the solid line rectangular waveform is the combined voltage.

Next, the function of the power amount correction calculation unit 34 shown in FIG. 5 will be described. The power amount correction calculation unit 34 performs a power amount correction calculation for keeping the power storage capacity of the power storage device E1 having a smaller power storage capacity in comparison with the other power storage devices E1 to E6. Since the power storage device E1 is equipped with a capacitor, it has a smaller storage capacity than the other power storage devices E2 to E6 equipped with secondary batteries, and the input / output voltage V _{E1 of the} power storage device is likely to fluctuate. For this reason, it is necessary to arrange the charge amount and discharge amount of the power storage device E1 within a certain period and to keep the voltage _VE1 within a certain range as much as possible.

First, the power amount correction calculation unit 34, based on each AC side input / output pattern information of the power conversion devices 10 to 60 output from the ON / OFF pattern calculation unit 33, corresponds to a half cycle (or one cycle) of each power storage device. Min)).

FIG. 8 is a bar graph showing a comparison of power consumption amounts (Q _E1 to Q _E6 ) of the power storage devices E1 to E6 when discharging for a half cycle is performed without performing the power amount correction calculation. As is apparent from FIGS. 6 and 7, the discharge period of the power storage device E1 is the shortest, and conversely, the discharge period of the power storage device E6 is the longest. For this reason, as shown in the bar graph of FIG. 8, the power consumption of each power storage device increases in the order of Q _E1 , Q _E2 _,.

Next, an example of power amount correction performed by the power amount correction calculation unit 34 and the ON / OFF pattern update calculation unit 35 and change of the output pattern of the power conversion device will be described with reference to FIGS. 9 and 10. Here, a case is shown in which the power storage device E2 has all of the energy Q _E1 for a half cycle that the power storage device E1 should originally bear. FIG. 9 shows a comparison of power consumption for a half cycle in this case. As shown in FIG. 9, the power consumption Q _E1 of the power storage device _E1 is added to the power consumption Q _E2 of the power storage device _E2 . Then, the total power consumption of the power storage device E1 is zero.

FIG. 10 is a specific waveform pattern of the inter-terminal voltage control of each AC side connection terminal of the

power conversion devices

10 and 20 for performing the above-described power amount correction. FIG. 10A is an AC side input / output pattern of the

power converters

10 and 20 before the power amount correction is performed, and FIG. 10B is a waveform pattern after the power amount correction. In the pattern before correction, the power storage device E1 performs the discharging operation in the period indicated by the shaded area A3 in FIG. The amount of power consumed during this period is the power consumption amount Q _E1 of the power storage device E1 shown in FIG.

In order to make the total power consumption of the half cycle of the power storage device E1 zero, the ON / OFF pattern update calculation unit 35 stores the same power amount based on the power consumption Q _E1 of the power storage device E1 in the period A3. The period required for the device E1 to charge is calculated, and a new waveform pattern is generated. Specifically, ON / OFF so that the AC side output of the power converter 10 is turned on in the negative direction (−V _E1 ) during the periods indicated by the oblique lines A1, A2, A4 and A5 in FIG. Change the OFF pattern. Instead, the ON / OFF pattern is changed so that the AC-side output of the power converter 20 is turned on in the positive direction (+ V _E2 ) during the periods indicated by the oblique lines in FIGS. B1, B2, B4, and B5.

By doing so, it is controlled so that the power storage device E2 apparently supplements the amount of power that the power storage device E1 has discharged, and the total power consumption of the power storage device E1 can be reduced to zero. .

FIG. 11 shows the AC side output patterns of the power converters 10 to 60 finally generated by the ON / OFF pattern update calculation unit 35 shown in FIG. Although each AC side input / output pattern of the

power converters

10 and 20 is changed, the voltage pattern that is synthesized and output is not changed, so that power exchange with the AC power supply system is not affected. Although the synthesized voltage waveform is not smooth compared to the command voltage 1, the current flowing between the power supply device 1 and the AC power supply system is smooth because power is transferred to and from the AC power supply system through a filter circuit in an actual system. A sinusoidal waveform.

In the example of the power amount correction and the ON / OFF pattern change performed by the power amount correction calculation unit 34 and the ON / OFF pattern update calculation unit 35 shown in FIGS. 9 to 11, the power amount only between the power storage devices E1 and E2. However, the power storage devices E3 to E6 can also be added to the power amount adjustment.

Figure 12 shows the power consumption Q _E1 of the power storage device _{_{E1 Q E1a, Q E1b, Q}} E1c, the power consumption Comparison of power storage device when each is shared storage device E2 ~ E5 divided into Q _{E 1 d} .

FIG. 13 is a timing chart showing an AC output pattern of each power converter when the power amount correction shown in FIG. 12 is performed. Although all AC side output patterns other than the power converter 60 have been changed, the combined voltage appearing at the AC side connection terminal 2 after being combined is not different from the combined voltage pattern obtained before the power amount correction.

The above is an overview of a control method for operating a power storage device equipped with a capacitor and a power storage device equipped with a secondary battery in the same power supply device.

A power storage device equipped with a capacitor does not need as much capacity as a power storage device equipped with a secondary battery as long as the input / output characteristics are comparable to those of other power storage devices, and there is no need to parallelize a large number of capacitor cells. For this reason, the power storage device in which the capacitor is mounted can lower the capacity cost of the power storage element than the power storage device in which another secondary battery is mounted. Furthermore, the charge / discharge cycle life of the capacitor is longer than that of the secondary battery, and the replacement frequency of the power storage device mounted with the capacitor is lower than that of the power storage device mounted with the secondary battery, and the running cost can be reduced.

In addition, this invention is not limited to the above-mentioned Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described.

Further, a part of the configuration of the embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of the embodiment. Further, it is possible to add / delete / replace other configurations for a part of the configuration of each embodiment.

In addition, each of the above-described configurations, functions, processing units, processing means, and the like may be realized by hardware by designing a part or all of them with, for example, an integrated circuit.

Further, each of the above-described configurations, functions, and the like may be realized by software by interpreting and executing a program that realizes each function by the processor.

1: Power supply device 2: AC side connection terminal 3: Central control device 31: Command voltage calculation unit, 32: Carrier calculation unit, 33: ON / OFF pattern calculation unit, 34: Electric energy correction calculation unit, 35: ON / OFF Pattern update calculation unit 36: Communication unit 4: Current measurement device 5: Voltage detection device 10-60: Power conversion device, 10d-60d: DC side connection terminal, 10a-60a: AC side connection terminals E1-E6: Power storage device 11: switching circuit, 111 to 114: MOSFET, D111 to D114: body diode 12: smoothing capacitor 13: control device, 131: communication unit, 132: data holding unit, 133: switch control / drive unit, 134: voltage determination Part,
14: Voltage measuring device,
C1 to C6: Carrier

Claims

A plurality of power conversion devices each having a DC side connection terminal to which a power storage device capable of charging and discharging electric power is electrically connected, and an AC side connection terminal, each of the plurality of power conversion devices being connected to each AC side A power supply device that can be connected to an AC power supply system by electrically connecting terminals in series,
The plurality of power conversion devices are classified into at least two groups,
The combination of the positive electrode active material and negative electrode active material of the power storage element built in the power storage device connected to the DC side connection terminal of the power conversion device constituting the group is the same in the group,
The power supply device, wherein a combination of the positive electrode active material and the negative electrode active material of the power storage element incorporated in the power storage device is different between the groups.
The power supply device according to claim 1,
A power supply device further comprising a central control device that communicates with the plurality of power conversion devices wirelessly or by wire to control voltage output of the AC side connection terminals of each of the plurality of power conversion devices. .
The power supply device according to claim 1 or 2,
The group includes a first group and a second group,
The power storage device connected to the DC side connection terminal of the power conversion device constituting the first group is equipped with a capacitor as the power storage element,
The power storage device connected to the DC side connection terminal of the power conversion device constituting the second group includes a secondary battery as the power storage element.
The power supply device according to claim 3,
The central control device controls the plurality of power conversion devices so as to keep an input / output voltage of a power storage device mounted with the capacitor constant when connected to the AC power supply system. .
The power supply device according to claim 3 or 4,
The capacitor is an electric double layer capacitor or a lithium ion capacitor, and the secondary battery is a lead storage battery or a lithium ion secondary battery.