[go: up one dir, main page]

WO2018159383A1 - Dispositif de commande de conversion de courant, système de production d'énergie et procédé de commande de conversion de courant - Google Patents

Dispositif de commande de conversion de courant, système de production d'énergie et procédé de commande de conversion de courant Download PDF

Info

Publication number
WO2018159383A1
WO2018159383A1 PCT/JP2018/005974 JP2018005974W WO2018159383A1 WO 2018159383 A1 WO2018159383 A1 WO 2018159383A1 JP 2018005974 W JP2018005974 W JP 2018005974W WO 2018159383 A1 WO2018159383 A1 WO 2018159383A1
Authority
WO
WIPO (PCT)
Prior art keywords
power
voltage
power conversion
output
converter
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2018/005974
Other languages
English (en)
Japanese (ja)
Inventor
公久 古川
尊衛 嶋田
充弘 門田
泰明 乗松
輝 米川
叶田　玲彦
馬淵　雄一
宮田　博昭
治郎 根本
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Ltd
Original Assignee
Hitachi Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hitachi Ltd filed Critical Hitachi Ltd
Publication of WO2018159383A1 publication Critical patent/WO2018159383A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
    • G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
    • G05F1/66—Regulating electric power
    • G05F1/67—Regulating electric power to the maximum power available from a generator, e.g. from solar cell
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
    • H02M7/42—Conversion of DC power input into AC power output without possibility of reversal
    • H02M7/44—Conversion of DC power input into AC power output without possibility of reversal by static converters
    • H02M7/48—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode

Definitions

  • the present invention relates to a power conversion control device, a power generation system, and a power conversion control method.
  • a photovoltaic power generation system (1) includes a plurality of solar cell groups (2a, 2b to 2n) and each of these solar cell groups. And a plurality of chopper units (3a, 3b to 3n) for boosting a DC voltage obtained from each of the solar cell groups, and controlling the output currents of these chopper units, respectively.
  • the operating point control means (6a, 6b to 6n) for optimizing the operating point of the group and obtaining the maximum output from the solar cell group and the DC voltage obtained from the plurality of chopper units are input, And an inverter (4) that converts and outputs the AC power.
  • the direct-current power obtained from a solar cell fluctuates with changes in the amount of sunlight and temperature. For this reason, when the direct-current power generated in the solar cell decreases and the output voltage decreases, the operation of the inverter may become unstable. For this reason, generally, when the output voltage of the solar cell reaches the lower limit value of the preset input voltage of the inverter, the inverter is controlled so that the input voltage to the inverter becomes constant. However, if the input voltage to the inverter is controlled to be constant, the power conversion device may become unstable, and there is a problem that the energy generated in the solar cell cannot be used efficiently as power. It was.
  • the present invention has been made in view of the above-described circumstances, and an object thereof is to provide a power conversion control device, a power generation system, and a power conversion control method for operating a power conversion device stably with high efficiency.
  • the power conversion control device of the present invention provides output power to a power conversion device that converts the DC voltage to an AC voltage when the DC voltage output from the DC power source exceeds a predetermined threshold voltage.
  • the input current to the power converter has a monotonically increasing relationship with the DC voltage.
  • a monotonic increase control unit for controlling the power converter.
  • the power conversion device can be stably operated with high efficiency.
  • 1 is a block diagram of a photovoltaic power generation system according to a first embodiment of the present invention. It is a circuit diagram of the inverter in a 1st embodiment. It is a flowchart of the control program in 1st Embodiment. It is an operation characteristic figure of a power converter when a solar cell characteristic is constant in a 1st embodiment. It is an operation characteristic figure of a power converter when a solar cell characteristic changes in a 1st embodiment. It is a flowchart of the control program in a comparative example. It is an operation characteristic figure of a power converter when a solar cell characteristic changes in a comparative example. It is a block diagram of the solar energy power generation system by 2nd Embodiment of this invention. It is a circuit diagram of the converter in a 2nd embodiment. It is a block diagram of the solar energy power generation system by 3rd Embodiment of this invention.
  • FIG. 1 is a block diagram of a photovoltaic power generation system S1 according to the first embodiment of the present invention.
  • the solar power generation system S ⁇ b> 1 includes a solar battery 10 (DC power supply), a power conversion device 20, a sensor unit 30, and a power conversion control device 40, and is connected to a system voltage source 60.
  • the power conversion device 20 is generally called a PCS (Power Conditioning System), and includes a smoothing capacitor 21 and an inverter 22.
  • PCS Power Conditioning System
  • the power conversion device 20 converts the DC power output from the solar cell 10 into AC power and supplies it to the system voltage source 60.
  • the input terminals of the power converter 20 and the point A, the voltage is referred to as the input voltage V DC (direct current voltage) of the point A, referred to as an input current I DC current.
  • the input terminal of the inverter 22 is a point B, and the current at the point B is called an input current I INV .
  • FIG. 2 is a circuit diagram of the inverter 22. As shown, a full bridge circuit is generally used as the inverter 22.
  • the sensor unit 30 measures the output current I AC of the inverter 22.
  • the output voltage V AC may be calculated or estimated from the control information of the inverter 22.
  • the sensor unit 30 may measure the output voltage V AC in addition to the output current I AC of the inverter 22.
  • the power conversion control device 40 controls the power conversion device 20.
  • the power conversion control device 40 includes hardware as a general computer such as a CPU (Central Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory).
  • the ROM is executed by the CPU. Control program and various data are stored.
  • the function of the power conversion control device 40 realized by a control program or the like is shown as a block. That is, the power conversion control device 40 includes an input current calculation unit 41 (monotonic increase control unit), an active power calculation unit 42 (monotonic increase control unit), an MPPT calculation unit 44 (constant power control unit), and a switching unit 45. And an active power control unit 46.
  • the MPPT calculation unit 44 provides a command value (effective output power P AC (output power, not shown)) of the inverter 22 ( P AC1 *) is calculated.
  • the constant K is determined in advance according to the target power to be output by the power conversion device 20, the characteristics of the solar cell 10, and the like.
  • the switching unit 45 selects one of the command values P AC1 * and P AC2 * output from the MPPT calculation unit 44 and the active power calculation unit 42 and outputs the selected value as the output power command value P AC *.
  • the active power control unit 46 receives the output voltage V AC and the output current I AC of the power converter 20 from the sensor unit 30, and the effective output power P AC of the inverter 22 approaches the output power command value P AC *.
  • the inverter 22 is feedback controlled.
  • the sensor unit 30 may measure only the output current I AC of the inverter 22 and calculate or estimate the output voltage V AC from the control information of the inverter 22.
  • FIG. 3 is a flowchart of a control program executed in the power conversion control device 40.
  • the power conversion control device 40 determines whether or not the input voltage V DC is equal to or lower than a predetermined threshold voltage V TH .
  • step S110 the operation mode of the power conversion control device 40 is set to the normal control mode in step S120.
  • the “normal control mode” refers to an operation mode in which the command value P AC1 * calculated by the MPPT calculation unit 44 in the switching unit 45 is selected as the output power command value P AC *.
  • step S110 the process proceeds to step S140, and the operation mode of the power conversion control device 40 is set to the monotonically increasing mode.
  • the “monotonically increasing mode” refers to an operation mode in which the command value P AC2 * calculated by the active power calculation unit 42 in the switching unit 45 is selected as the output power command value P AC *. That is, as monotonically increasing with respect to the input current I DC (i.e., as the input current I DC is proportional to the input voltage V DC), refers to a control of setting the input voltage V DC.
  • step S120 or step S140 ends, the process returns to step S110, and the processes after step S110 are repeated. Therefore, if the input voltage V DC is less than or equal to the threshold voltage V TH , the monotonically increasing mode is maintained, and if the input voltage V DC exceeds the threshold voltage V TH , the normal control mode is maintained.
  • the MPPT calculation unit 44 continues to output a constant command value P AC1 *.
  • FIG. 4 is an operation characteristic diagram of the power conversion device 20 when the solar cell characteristics are constant.
  • V DC and I DC are the input voltage and input current to the power conversion device 20
  • I INV is the input current to the inverter 22.
  • the solar cell characteristic L 1 is a characteristic realized by the solar cell 10, and as the input current I DC (output current from the solar cell 10 to the power converter 20) of the power converter 20 increases, the power The input voltage VDC of the converter 20 tends to decrease.
  • the constant power characteristic L 2 is a characteristic that the active power control unit 46 intends to realize based on the command value P AC1 * output from the MPPT calculation unit 44. As described above, assuming the operation of a short time, MPPT computing unit 44 is selected as to continue to output a constant command value P AC1 *, finger command value P AC1 * output power command value P AC * When active power control unit 46 in accordance with the constant-power characteristic L 2, controls the inverter 22.
  • the operating point at the point A shown in FIG. 1 is the operating point A 1 on the solar cell characteristic L 1
  • the input voltage V DC becomes the voltage V b shown in FIG. 4 at a certain moment.
  • the operating point at the point A becomes the operating point A 3 on the solar cell characteristic L 1
  • the input voltage V DC becomes the voltage V c shown in FIG. 1 at a certain moment.
  • the operating point at point A is the operating point A 4 on the solar cell characteristic L 1
  • the operating point at point B is the operating point B 4 on the constant power characteristic L 2 . That is, the input current I INV to the inverter 22 becomes larger than the input current I DC to the power converter 20. Then, the electric charge corresponding to the difference between the two currents is discharged from the smoothing capacitor 21, and the input voltage VDC decreases. As a result, the input voltage V DC goes to zero voltage as time passes.
  • the intersection of the characteristics L 1 and L 2 at the voltage V LIM is not an operating point where the operation is stable, but an unstable operating point. Therefore, this voltage V LIM is referred to as “stable operation limit voltage”.
  • the threshold voltage V TH described in step S110 in FIG. 3 is set to a value that is slightly higher (with a slight margin) than the stable operation limit voltage V LIM . Therefore, actually, before the input voltage V DC reaches the stable operation limit voltage V LIM , the operation mode transits to the monotonically increasing mode (S140).
  • FIG. 5 is an operation characteristic diagram of the power conversion device when the solar cell characteristics change.
  • characteristics L 11 to L 14 are solar cell characteristics when the amount of sunshine decreases sequentially and the power generation capacity decreases.
  • the characteristic L 3 is a characteristic to be realized by the active power control unit 46.
  • the operation mode In the range where the input voltage V DC exceeds the threshold voltage V TH , the operation mode is the normal control mode. Therefore, the characteristic L 3 is the same as the constant power characteristic L 2 (see FIG. 4) in the range.
  • the operation mode is a monotonically increasing mode when the input voltage V DC is equal to or lower than the threshold voltage V TH
  • the characteristic L 3 is a characteristic in which the input current I DC is proportional to the input voltage V DC .
  • the stable operating point is Q 1 .
  • the stable operating point becomes Q 2 .
  • the input voltage V DC at the operating point Q 2 matches the threshold voltage V TH . Therefore, when the input voltage V DC further decreases, the operation mode becomes a monotonically increasing mode.
  • the stable operating point becomes Q 3
  • the stable operating point becomes Q 4. become.
  • the characteristic L 3 is a combination of the constant power characteristic and the proportional characteristic. Therefore, there are stable operating points Q 1 to Q 4 in various solar cell characteristics L 11 to L 14 .
  • a comparative example will be described.
  • the configuration of the comparative example is the same as that of the first embodiment (see FIG. 1), but a constant voltage calculation unit (not shown) is provided instead of the input current calculation unit 41 and the active power calculation unit 42. The point is different.
  • the constant voltage calculation unit (not shown) calculates a command value P AC2 * such that the input voltage V DC matches the threshold voltage V TH and outputs the command value P AC2 * to the switching unit 45.
  • FIG. 6 is a flowchart of a control program executed by the power conversion control device 40 in this comparative example.
  • step S130 is executed in this comparative example instead of step S140 in the first embodiment. That is, when the input voltage V DC becomes equal to or lower than the threshold voltage V TH , the process proceeds to step S130, and the operation mode is set to the constant voltage mode.
  • the “constant voltage mode” refers to an operation mode in which a command value P AC2 * output by a constant voltage calculation unit (not shown) is selected as the output power command value P AC *.
  • FIG. 7 is an operation characteristic diagram of the power conversion device 20 when the solar cell characteristics change in this comparative example.
  • the characteristic L 4 is a characteristic to be realized by the active power control unit 46 (see FIG. 1) of this comparative example.
  • the operation mode In the range where the input voltage V DC exceeds the threshold voltage V TH , the operation mode is the normal control mode. Therefore, the characteristic L 4 is the same as the constant power characteristic L 2 (see FIG. 4) in the range.
  • the operation mode becomes the constant voltage mode, and therefore the input voltage VDC becomes a constant value (threshold voltage V TH ) in the characteristic L 4 .
  • the stable operating points are Q 1 and Q 2 as in the case of FIG. Since the input voltage V DC at the operating point Q 2 matches the threshold voltage V TH, when the power generation capability of the solar cell 10 further decreases, the operation mode becomes the constant voltage mode.
  • the solar cell characteristic becomes L 13
  • the stable operating point becomes Q 13
  • the solar cell characteristic becomes L 14
  • the power conversion control device 40 stops the power conversion device 20 and restarts the power conversion device 20.
  • FIG. 8 is a block diagram of a photovoltaic power generation system S2 according to the second embodiment of the present invention.
  • parts corresponding to those in FIGS. 1 to 7 are denoted by the same reference numerals, and description thereof may be omitted.
  • the photovoltaic power generation system S2 is applied with a power conversion device 20A instead of the power conversion device 20.
  • the other configuration of the solar power generation system S2 is the same as that of the first embodiment.
  • a smoothing capacitor 24 and a converter 23 are inserted between the input terminal (point A) and the smoothing capacitor 21.
  • FIG. 9 is a circuit diagram of the converter 23.
  • the DC voltage input to the converter 23 is converted into an AC voltage in the full bridge circuit 23a.
  • the AC voltage is stepped up or stepped down through the resonant capacitor 23d and the insulating transformer 23c and supplied to the diode bridge 23b.
  • the diode bridge 23b the boosted or stepped down AC voltage is rectified and output.
  • the converter 23 boosts or steps down the input DC voltage and outputs it.
  • the converter 23 boosts or steps down the DC voltage input to the power conversion device 20 ⁇ / b> A and supplies it to the inverter 22.
  • the efficiency of the inverter 22 can be increased.
  • FIG. 10 is a block diagram of a photovoltaic power generation system S3 according to the third embodiment of the present invention.
  • parts corresponding to those in FIGS. 1 to 9 are denoted by the same reference numerals, and description thereof may be omitted.
  • the photovoltaic power generation system S3 is applied with a power conversion device 20B instead of the power conversion device 20A.
  • power converter 20B a plurality of systems of smoothing capacitor 24, converter 23, smoothing capacitor 21, and inverter 22 are provided.
  • the configuration of these individual components 21 to 24 is the same as that of the second embodiment.
  • the plurality of inverters 22 are connected in series.
  • the configuration of the photovoltaic power generation system S3 other than the above is the same as that of the second embodiment. According to this embodiment, since the some inverter 22 is connected in series, the power converter device 20B can output a higher alternating voltage.
  • the present invention is not limited to the above-described embodiments, and various modifications can be made.
  • the above-described embodiments are illustrated for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described.
  • a part of the configuration of an embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of an embodiment.
  • the control lines and information lines shown in the figure are those that are considered necessary for the explanation, and not all the control lines and information lines that are necessary on the product are shown. Actually, it may be considered that almost all the components are connected to each other. Examples of possible modifications to the above embodiment are as follows.
  • the DC power source is not limited to the solar battery 10, and various DC power sources such as a primary battery, a secondary battery, a wind power generator, and a thrust power generator can be applied.
  • the example in which the input voltage V DC and the input current I DC are proportional to each other has been described as the “monotonically increasing mode (S140)”.
  • the input voltage V DC and the input current I DC do not necessarily have a proportional relationship.
  • an operating point at which the maximum output can be extracted from the solar cell 10 is obtained, and the characteristics connecting these operating points are used as the characteristics in the monotonically increasing mode. You may apply.
  • FIG. 3 has been described as software processing using a program in each of the above-described embodiments, but part or all of the processing is ASIC (Application Specific Integrated Circuit). Alternatively, it may be replaced with hardware processing using FPGA (field-programmable gate array) or the like.
  • ASIC Application Specific Integrated Circuit
  • FPGA field-programmable gate array

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Automation & Control Theory (AREA)
  • Inverter Devices (AREA)
  • Control Of Electrical Variables (AREA)

Abstract

La présente invention concerne un dispositif de commande de conversion de courant permettant de faire fonctionner de manière stable un dispositif de conversion de courant avec une efficacité élevée. Par conséquent, l'invention concerne : une unité de commande de puissance constante (44) qui, lorsqu'une tension continue (VDC) produite par une alimentation en courant continu (10) dépasse une tension seuil prescrite (VTH), commande un dispositif de conversion de courant (20) pour convertir la tension continue (VDC) en une tension alternative de telle sorte qu'une puissance de sortie (PAC) est sensiblement constante ; et des unités de commande d'augmentation monotone (41, 42), lesquelles, lorsque la tension continue (VDC) est inférieure ou égale à la tension seuil (VTH), commandent le dispositif de conversion de courant (20) de telle sorte qu'un courant d'entrée (IDC) vers le dispositif de conversion de courant (20) a une relation d'une augmentation monotone par rapport à la tension continue (VDC).
PCT/JP2018/005974 2017-03-01 2018-02-20 Dispositif de commande de conversion de courant, système de production d'énergie et procédé de commande de conversion de courant Ceased WO2018159383A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2017037964 2017-03-01
JP2017-037964 2017-03-01

Publications (1)

Publication Number Publication Date
WO2018159383A1 true WO2018159383A1 (fr) 2018-09-07

Family

ID=63371067

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2018/005974 Ceased WO2018159383A1 (fr) 2017-03-01 2018-02-20 Dispositif de commande de conversion de courant, système de production d'énergie et procédé de commande de conversion de courant

Country Status (1)

Country Link
WO (1) WO2018159383A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63133214A (ja) * 1986-11-26 1988-06-06 Nissin Electric Co Ltd 系統連系太陽光発電装置のインバ−タ制御方式
WO1988004801A1 (fr) * 1986-12-19 1988-06-30 Stuart Maxwell Watkinson Appareil de transfert de puissance electrique
WO2005020420A1 (fr) * 2003-08-22 2005-03-03 The Circle For The Promotion Of Science And Engineering Convertisseur de puissance, moteur, systeme btb et systeme inverseur de liaison de systeme

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63133214A (ja) * 1986-11-26 1988-06-06 Nissin Electric Co Ltd 系統連系太陽光発電装置のインバ−タ制御方式
WO1988004801A1 (fr) * 1986-12-19 1988-06-30 Stuart Maxwell Watkinson Appareil de transfert de puissance electrique
WO2005020420A1 (fr) * 2003-08-22 2005-03-03 The Circle For The Promotion Of Science And Engineering Convertisseur de puissance, moteur, systeme btb et systeme inverseur de liaison de systeme

Similar Documents

Publication Publication Date Title
JP4457692B2 (ja) 最大電力追尾制御方法及び電力変換装置
JP7301997B2 (ja) 最適化器、太陽光発電システム、及び太陽電池モジュールのためのｉｖ曲線スキャニング方法
JP5320144B2 (ja) 太陽電池の最大出力電力追従制御装置
AU2020268909B2 (en) Systems and methods for photovoltaic direct current (DC) bus control
US10447070B2 (en) Solar energy system with built-in battery charger and its method
CN103069354B (zh) 用于在最大功率的操作点处操作光伏发电装置的方法
EP4293896B1 (fr) Procédé et dispositif de suivi de point de puissance maximal
WO2022087955A1 (fr) Procédé et appareil de commande de tension de bus pour système photovoltaïque
US20130030587A1 (en) System and method for power curtailment in a power network
JP6539172B2 (ja) 電源装置
WO2017016485A1 (fr) Procédé et dispositif de régulation d'impulsion dans un convertisseur multi-niveau, et convertisseur multi-niveau
JP3949350B2 (ja) 連系装置
CN110521077B (zh) 具有逆变器输入电压控制的电源系统
CN117811083A (zh) 供电电路的放电控制方法、供电设备及储能设备
AU2023200028B2 (en) Alternating current electrolysis system, and method and device for controlling the same
US8942017B2 (en) Energy storage system and method thereof
JP2000341959A (ja) 発電システム
WO2015145971A1 (fr) Dispositif de conversion de courant et procédé de conversion de courant
KR20190101672A (ko) 최대전력점 추종 제어를 위한 태양광 발전 시스템
JP2023553345A (ja) 直流／直流コンバータおよびその制御方法
JP6106568B2 (ja) 電力変換装置
WO2018159383A1 (fr) Dispositif de commande de conversion de courant, système de production d'énergie et procédé de commande de conversion de courant
WO2022107583A1 (fr) Système d'alimentation et procédé de commande d'un système d'alimentation
JP2016045803A (ja) 太陽光電力制御装置
JP2000020149A (ja) 太陽光インバータ装置

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 18760887

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 18760887

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: JP