WO2019007479A1 - Équilibrage de tension de convertisseur de courant - Google Patents

Équilibrage de tension de convertisseur de courant Download PDF

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Publication number
WO2019007479A1
WO2019007479A1 PCT/EP2017/066524 EP2017066524W WO2019007479A1 WO 2019007479 A1 WO2019007479 A1 WO 2019007479A1 EP 2017066524 W EP2017066524 W EP 2017066524W WO 2019007479 A1 WO2019007479 A1 WO 2019007479A1
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WO
WIPO (PCT)
Prior art keywords
mmc
phase
grid
voltage
circuit breaker
Prior art date
Application number
PCT/EP2017/066524
Other languages
English (en)
Inventor
Christian Schlegel
Michail VASILADIOTIS
Beat Buchmann
Original Assignee
Abb Schweiz Ag
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 Abb Schweiz Ag filed Critical Abb Schweiz Ag
Priority to PCT/EP2017/066524 priority Critical patent/WO2019007479A1/fr
Publication of WO2019007479A1 publication Critical patent/WO2019007479A1/fr

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Classifications

    • 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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/36—Means for starting or stopping converters
    • 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
    • H02M7/483—Converters with outputs that each can have more than two voltages levels
    • 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
    • H02M7/483—Converters with outputs that each can have more than two voltages levels
    • H02M7/4835—Converters with outputs that each can have more than two voltages levels comprising two or more cells, each including a switchable capacitor, the capacitors having a nominal charge voltage which corresponds to a given fraction of the input voltage, and the capacitors being selectively connected in series to determine the instantaneous output voltage
    • 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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0003—Details of control, feedback or regulation circuits
    • H02M1/0025—Arrangements for modifying reference values, feedback values or error values in the control loop of a converter
    • 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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection
    • 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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Definitions

  • the present disclosure relates to a method for voltage balancing between phase-legs of a Modular Multilevel Converter (MMC).
  • MMC Modular Multilevel Converter
  • An MMC also known as Chain-Link Converter (CLC)
  • CLC Chain-Link Converter
  • Each converter cell comprises, in the form of a half-bridge (also known as monopolar) or full-bridge (also known as H- bridge or bipolar) circuit, a capacitor for storing energy and power
  • IGBT Insulated Gate Bipolar Transistor
  • GTO Gate-Turn-Off Thyristor
  • IGCT Commutated Thyristor
  • MOSFET Field-Effect Transistor
  • MMC inner control A dedicated part of the closed-loop control (MMC inner control) is used to keep the individual branches of the MMC balanced. "Balanced” means that the voltages across the individual branches do not deviate but instead converge asymptotically to their mean value.
  • the balancing is achieved through two different mechanisms: a) active power transfer between the three converter phase-legs (also referred to as horizontal balancing) and b) active power transfer between the upper and lower branches of the same phase-leg (also referred to as vertical balancing).
  • the horizontal balancing control loop compares the three UDc_sum values (the sum of the cells' capacitor voltages ( ⁇ U ce ii, I. N) in one phase-leg) and, in case of an unbalance between the three voltages, creates a circulating current to equalise the UDc_sum values.
  • this circulating current is of the railway supply frequency, e.g. 16.7 Hz, to interact with the respective single-phase side converter voltage and achieve active power transfer.
  • the vertical balancing control loop compares the voltages of the upper branches with the voltages of their corresponding lower branches and, in case of an unbalance between those voltage pairs, creates a circulating current to equalise the upper and lower branch voltages.
  • This circulating current is of the three-phase utility grid frequency, e.g. 50 Hz, to interact with the respective three-phase side converter voltage UDc_sum and achieve active power transfer. This concept works well when the converter pulses are released and the MMC is connected to both the three-phase and single-phase grids.
  • the converter pulses are released but the MMC is disconnected from one or both of the three-phase and single-phase grids.
  • These conditions include, but are not limited to: starting up of the converter (in particular during magnetising of the grid transformer(s)), reactive power compensation mode (Volt-Ampere Reactive (VAR)-compensation mode).
  • VAR Volt-Ampere Reactive
  • the converter is typically disconnected from the single-phase grid, and may also be disconnected from the three-phase grid if a pre-charge module is used on three-phase side of the MMC.
  • Embodiments of the present invention relate to a method of controlling a an MMC configured to be connected between a first power grid and a second power grid, wherein the first power grid is a three-phase AC grid.
  • Embodiments also describe a voltage balancing controller, comprised in a control arrangement of the MMC, to implement said method, in order to keep all branches of an MMC at the same voltage level.
  • the voltage balancing controller may not be fully operational under certain operating conditions in accordance with the prior art, especially when the converter is disconnected from the second grid (as discussed in the background section above).
  • embodiments of the method of the present disclosure may be used. As soon as the MMC is modulating (i.e. pulses are released to drive the valves, semiconductor switches, of the MMC), a non-zero voltage reference for the second side of the MMC is sent from the controller to the MMC. This non-zero voltage reference ensures the proper active power transfer between the converter phase-legs of the MMC for balancing purposes.
  • a method for voltage balancing between phase-legs of a Modular Multilevel Converter comprising a plurality of series connected converter cells. Each cell comprises an energy storage and a plurality of semiconductor switches.
  • the MMC is configured to be connected between a first power grid, which is a three-phase AC grid, via a first circuit breaker of a first side of the MMC, and a second power grid, having a nominal voltage UR, n0 m, via a second circuit breaker of a second side of the MMC.
  • the MMC is disconnected from the second grid by means of the second circuit breaker.
  • the method comprises setting a non-zero voltage reference for the second side voltage, sending firing pulses for controlling the semiconductor switches of the converter cells, and balancing the phase-leg voltages of the phase-legs by means of the voltage resulting from the set voltage reference on the second side of the MMC.
  • a computer program product comprising computer-executable components for causing a control arrangement to perform the method of any preceding claim when the computer-executable components are run on processing circuitry comprised in the control arrangement.
  • a control arrangement for voltage balancing between phase-legs of an MMC in which each phase-leg comprises a plurality of series connected converter cells, each cell comprising an energy storage and a plurality of semiconductor switches, the MMC being configured to be connected between a first power grid, which is a three-phase AC grid, via a first circuit breaker of a first side of the MMC, and a second power grid, having a nominal voltage, via a second circuit breaker of a second side of the MMC, the MMC being disconnected from the second grid by means of the second circuit breaker.
  • the control arrangement comprises processing circuitry, and data storage storing instructions executable by said processing circuitry whereby said control arrangement is operative to set a non-zero voltage reference for the second side voltage, send firing pulses for controlling the semiconductor switches of the converter cells, and balance the phase-leg voltages of the phase-legs by means of a voltage resulting from the set voltage reference on the second side of the MMC.
  • the non-zero voltage reference results in a voltage being produced at the second side of the MMC, allowing balancing of the voltages of the phase-legs.
  • Fig l is a schematic circuit diagram of an embodiment of an MMC having a double-star topology, in accordance with the present invention.
  • Fig 2 is a schematic circuit diagram of an embodiment of a full-bridge converter cell, in accordance with the present invention.
  • Fig 3 is a schematic block diagram of an embodiment of how an MMC is connected between a three-phase grid and a single-phase grid, in accordance with the present invention.
  • Fig 4 is a schematic flow chart of an embodiment of a method of the present invention.
  • Embodiments of the present invention are below discussed primarily with reference to the example of a railway intertie, where the MMC is a three-to- single-phase AC converter, e.g. in a double-star configuration as in figure 1, having a (first) three-phase side connected to a (first) three-phase grid and a (second) single-phase side connected to a (second) single-phase grid.
  • embodiments of the present invention may also be useful for other types of MMC, e.g. a AC-to-DC converter where the second side is a DC side connected to a DC grid, or a three-phase-to-three-phase converter where both the first and second sides are three-phase sides connected to first and second three-phase grids.
  • a AC-to-DC converter where the second side is a DC side connected to a DC grid
  • a three-phase-to-three-phase converter where both the first and second sides are three-phase sides connected to first and second three-phase grids.
  • the MMC ⁇ is in a double-star (also called double-Y or -wye) topology and connected between a three-phase AC grid 5a, having the three Alternating Current (AC) phases a, b and c, and a single-phase AC grid 5b, e.g. a railway grid, formed between two phases (outputs) of the MMC.
  • a three-phase AC grid 5a the line current of phase a is given as iLi, of phase b as 1L2 and of phase c as 1L3.
  • the current is given as iR and the voltage as UR.
  • the double-star topology comprises one phase leg 2 for each phase a, b and c of the three-phase grid 5a, each phase leg 2 comprising two branches 3 (also called arms), a first (also called upper) branch 3a and a second (also called lower) branch 3b, of series connected (also called chain-linked or cascaded) converter cells 4.
  • the first phase a connects a first phase leg 2a at a point Li between the first and second branches 3a and 3b of said first phase leg 2a
  • the second phase b connects a second phase leg 2b at a point L2 between the first and second branches 3a and 3b of said second phase leg 2b
  • the third phase c connects a third phase leg 2c at a point L3 between the first and second branches 3a and 3b of said third phase leg 2c.
  • a control arrangement 10, comprising the voltage balancing controller, of the converter 1 controls the converter, e.g. voltage balances the branches 3 horizontally and vertically and sends firing pulses to the semiconductor switches S of the converter cells 4.
  • the control arrangement 10 may comprise a central part, e.g. comprising the voltage balancing controller, and distributed parts, e.g. cell controllers associated with each converter cell.
  • the voltage and current over the first branch 3a of the first leg 2a is given as uia and iia, respectively.
  • the voltage and current over the second branch 3b of the first leg 2a is given as uib and iib, respectively.
  • the voltage and current over the first branch 3a of the second leg 2b is given as u2a and 12a, respectively.
  • the voltage and current over the second branch 3b of the second leg 2b is given as u2b and 12b, respectively.
  • the voltage and current over the first branch 3a of the third leg 2c is given as u3a and 13a, respectively.
  • FIG. 2 illustrates an MMC cell 4, e.g. of a converter 1 as illustrated in figure 1.
  • the cell 4 comprises an energy storage 21, typically a capacitor arrangement comprising at least one capacitor, over which a DC voltage of the cell is formed.
  • a plurality of semiconductor switches S form a half-bridge (also called monopolar) or full-bridge (also called H-bridge or bipolar) topology, herein (as is preferred in some embodiments of the invention) four semiconductor switches S1-S4 form a full-bridge topology.
  • Figure 3 illustrates an embodiment of how an MMC 1 in accordance with the present invention may be connected between a first power grid 5a, here again exemplified as a three-phase AC grid 5a, in this case of 50 Hz, and a second power grid, here again exemplified as a single phase AC grid 5b, in this case of 16.7 Hz e.g. a railway grid.
  • the MMC may e.g. be as shown in figure 1.
  • the MMC On the single-phase side of the MMC 1, the MMC is connectable to the single- phase grid 5b via a second circuit breaker 31b, able to disconnect the MMC from the single-phase grid (in which case embodiments of the present invention are especially useful).
  • the MMC is typically also connected via a second grid transformer 32b (e.g. a rail grid transformer) or, alternatively, via a line inductor, typically positioned in series between the MMC and the second circuit breaker.
  • the nonzero voltage reference UR, re f preferably has a non-zero frequency in order to not saturate said grid transformer.
  • the non-zero voltage reference UR, re f may be allowed to have a frequency of zero, i.e. to substantially be direct current (DC). That the reference voltage UR, re f is non-zero thus refers to the amplitude (or DC voltage, in case of zero frequency) not being zero for enabling horizontal voltage balancing between the phase legs 2 of the MMC 1.
  • the MMC On the three-phase side of the MMC 1, the MMC is connectable to the three- phase grid 5a via a first circuit breaker 31a.
  • the first circuit breaker 31a is ON (conducting/closed) and thus connecting the MMC to the three-phase grid, e.g.
  • the first circuit breaker 31a when acting as a Static Synchronous Compensator (STATCOM) for the three-phase grid 5a, and in some other embodiments of the invention the first circuit breaker 31a is OFF (not conducting/open) and thus disconnecting the MMC from the three- phase grid, e.g. during start-up of the MMC by means of a pre-charge module 34.
  • the MMC is typically also connected via a first grid transformer 32a (e.g. a utility grid transformer), typically positioned in series between the MMC and the first circuit breaker.
  • an additional circuit breaker in the form of a transformer disconnector 34 is positioned in series between the MMC and the first grid transformer 32a, able to disconnect the MMC from said first grid transformer.
  • Other standard devices may also be connected on the three-phase side of the MMC, depending on the application, such as a grid filter 33, e.g. connected between MMC and the first grid transformer.
  • some embodiments of the present invention may be especially useful during start-up of the MMC, when the MMC is disconnected from the single-phase grid but being charged from its three-phase side.
  • the MMC is connected to the three-phase grid during such a start-up.
  • a pre-charge module 35 may be used during start-up for charging from the three-phase side of the MMC, in which case the MMC is typically disconnected from the three-phase grid 5a, and may also be disconnected from the first grid transformer 32a by means of the transformer disconnector 34, during start-up.
  • the pre-charge module 35 is typically connected between the MMC and the first grid transformer 32a or the transformer disconnector 34 (if present).
  • Embodiments of the invention relate to a method of controlling an MMC l.
  • Embodiments of the invention also relate to a controller 10, connected to the MMC, to implement said method.
  • a non-zero voltage reference UR, re f for the single-phase side voltage UR is provided by the controller 10 to the MMC l.
  • This non-zero voltage reference UR, re f ensures the proper active power transfer between the three converter phase-legs 2a-c (also known as horizontal balancing), which is described above.
  • the voltage reference UR, re f adds the missing degree of freedom for achieving full MMC controllability.
  • the frequency of the voltage reference UR, re f can be set to any value and the amplitude of the voltage reference UR, re f has to be set to above zero, e.g. to between zero and UR.
  • the voltage reference UR,ref is preferably kept below the nominal voltage UR, n0 m, optimally as close to zero as possible while still allowing for the desired horizontal voltage balancing.
  • the converter cells 4 may be charged using a separate pre-charging module 35, while the utility grid transformer 32a is disconnected from the converter by means of the transformer disconnector 34. After the cells 4 are completely charged, the pre-charging module 35 is disconnected from the converter and the transformer 32a is connected to the converter 1 by closing the transformer disconnector 34, while still being disconnected from the grid 5a by means of the circuit breaker 31a. The stored energy of the cell 4 is then used to magnetize the transformer 32a by releasing pulses in a controlled manner, e.g. as described in EP 3 010 104. If the three-phase side as well as the single-phase side transformers 32a and 32b are magnetized simultaneously, the balancing of the branches 3 works as expected. There are however scenarios, whereby only the three-phase side transformer 32a is magnetized. These scenarios include one or more of the following:
  • the stored energy in the cells 4 is not sufficient to charge two
  • the MMC 1 is brought to a standby state, where only the three-phase grid 5a is connected to the MMC to keep the cells 4 charged.
  • This standby state allows a fast transition into active power transfer mode (ON state), while keeping energy consumption to a minimum.
  • the MMC l will only be operated in VAR-compensation mode on the three-phase grid 5a, making it unnecessary to connect the MMC to the single- phase grid 5b.
  • the three UDc_sum values diverge during the magnetising of the transformer if the voltage reference UR, re f of the single-phase side is kept at zero. This divergence may ultimately lead to a shutdown of the converter.
  • a non-zero voltage reference UR, re f is applied to the single-phase side as soon as the firing pulses are released, i.e. the MMC is modulating.
  • the resulting voltage adds the missing degree of freedom for achieving full MMC controllability.
  • horizontal balancing is enabled and therefore, the three UDc_sum values of the three phase-legs 2 will remain balanced.
  • the single-phase side voltage reference UR, re f is kept to a value of between zero volts and UR, n0 m, where UR, n0 m is the nominal single-phase grid voltage. The closer the voltage reference is to zero, the smaller the created losses are.
  • converters for rail network interties already have the capability of working as a STATCOM
  • utility companies may benefit from this capability not only for the single-phase side but also for the three-phase side. It may therefore be desirable to provide a VAR-compensation mode for the three-phase side as well as the single-phase side of the MMC 1.
  • some embodiments of the present invention may be especially useful when the MMC is functioning as a STATCOM.
  • a non-zero voltage reference UR, re f is applied to the single-phase side as soon as the pulses are released, i.e. the MMC is modulating.
  • the resulting voltage enables the horizontal balancing between the phase-legs 2. With horizontal balancing enabled, the three UDc_sum values may remain balanced.
  • the single-phase side voltage reference UR, re f is kept to a value of between zero volts and UR, n0 m , where UR, n0 m is the nominal single-phase grid voltage.
  • UR, re f is kept to a value of between zero volts and UR, n0 m , where UR, n0 m is the nominal single-phase grid voltage.
  • the method is for voltage balancing between the phase-legs 2 of an MMC 1.
  • Each phase-leg 2 comprising a plurality of series connected converter cells 4.
  • Each cell 4 comprises an energy storage 21 and a plurality of semiconductor switches S.
  • the MMC is configured to be connected (connectable) between a three-phase AC power grid 5a (herein called the first power grid) via a first circuit breaker 31a of a first (three- phase) side of the MMC, and a second power grid 5b, e.g.
  • the method comprises, setting Ml a non-zero voltage reference UR, re f for the second side voltage UR, which results in a voltage on the second side of the MMC even when not connected to the second grid 5b.
  • the method also comprises, before or after the setting Mi (as indicated by the double-headed arrow), sending M2 firing pulses for controlling the semiconductor switches S of the converter cells 4, i.e. the MMC is modulating.
  • the method also comprises balancing M3 the phase-leg voltages UDc_sum of the phase-legs 2 by means of the voltage resulting from the set Mi voltage reference on the second side of the MMC.
  • the method is performed during start-up of the MMC 1, e.g. as discussed as an example above.
  • the MMC 1 is disconnected from the first grid 5a by means of the first circuit breaker 31a and a pre-charging module 35 is connected to the first side of the MMC for charging the MMC during start-up.
  • the method is performed as part of a VAR- compensation mode of the MMC 1 in which the MMC acts as a STATCOM for compensating reactive power in the first power grid 5a, being a three-phase grid, as discussed as another example embodiment above.
  • the non-zero voltage reference UR, re f has an amplitude which is less than the nominal voltage UR, n0 m of the second grid 5b.
  • a second side voltage of the MMC which is reduced compared with the nominal voltage of the second grid 5b reduces the losses in the MMC and transformers.
  • the voltage reference is close to zero, but still not zero.
  • the non-zero voltage reference has a non-zero frequency. This is preferred especially when a second grid transformer 32b is used, since such a transformer risks being overcharged in case of a DC voltage on the second side of the MMC. In case a second grid transformer is not used, e.g. if a line inductor is used instead, the non-zero voltage reference may have a zero frequency.
  • the second grid 5b is a railway grid. Embodiments of the present invention may be especially useful for a railway intertie, but other types of single-phase or three-phase grids 5b are also contemplated. As mentioned herein the second grid 5b may preferably be a single-phase AC grid. However, in other embodiments of the present invention, the second grid may be e.g. a three-phase AC grid or a DC grid.
  • the second side, e.g. a single-phase side, of the MMC has a frequency of 16.7 Hz, e.g. 50/3 Hz, or 25 Hz, preferably 16.7 Hz. These are typical examples of railway grid frequencies used in different countries.
  • the first side of the MMC being a three-phase AC side has a frequency of 50 Hz or 60 Hz, preferably 50 Hz. These are typical examples of distribution grid frequencies used in different countries.
  • the MMC 1 has a double-star topology, e.g. as illustrated in figure 1. However, the invention is not limited to this topology, but may be used with any MMC topology, e.g. for AC-to-DC MMC or three- phase-to-three-phase MMC.
  • the plurality of semiconductor switches S1-S4 form a full-bridge topology. This is preferred to provide bidirectional functionality.
  • each of the plurality of semiconductor switches S comprises an IGCT.
  • IGCTs are currently preferred semiconductor devices for the switches S, any other semiconductor switch device may alternatively be used with embodiments of the invention, e.g. IGBT, GTO or MOSFET.
  • Embodiments of the method of the present invention may be performed by a control arrangement 10 of the converter 1, which control arrangement comprises processing circuitry associated with data storage.
  • the processing circuitry may be equipped with one or more processing units CPU in the form of microprocessor(s) executing appropriate software stored in associated memory for procuring required functionality.
  • processing units CPU e.g. an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a complex programmable logic device (CPLD), etc.
  • ASIC application specific integrated circuit
  • FPGA field programmable gate array
  • CPLD complex programmable logic device
  • Embodiments of the present invention may be conveniently implemented using one or more conventional general purpose or specialized digital computer, computing device, machine, or microprocessor, including one or more processors, memory and/or computer readable storage media programmed according to the teachings of the present disclosure.
  • the present invention includes a computer program product which is a non-transitory storage medium or computer readable medium (media) having instructions stored thereon/in which can be used to program a computer to perform any of the methods/processes of the present invention.
  • the storage medium can include, but is not limited to, any type of disk including floppy disks, optical discs, DVD, CD-ROMs, microdrive, and magneto-optical disks, ROMs, RAMs, EPROMs, EEPROMs, DRAMs, VRAMs, flash memory devices, magnetic or optical cards,
  • control arrangement 10 may be a computer program product as discussed herein.
  • the present disclosure has mainly been described above with reference to a few embodiments. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the present disclosure, as defined by the appended claims.

Abstract

La présente invention concerne un procédé d'équilibrage de tension entre des branches de phases (2) d'un convertisseur modulaire multiniveaux (MMC) (1). Chaque branche de phase comprend une pluralité de cellules de convertisseur connectées en série 4. Chaque cellule comprend un stockage d'énergie et une pluralité de commutateurs à semi-conducteurs. Le MMC est configuré pour être connecté entre un premier réseau électrique 5(a), qui est une grille CA triphasée, par l'intermédiaire d'un premier disjoncteur 3(1a) d'un premier côté du MMC, et un second réseau électrique (5b) ayant une tension nominale UR,nom, par l'intermédiaire d'un second disjoncteur 3(1b) d'un second côté du MMC. Le MMC est déconnecté du second réseau au moyen du second disjoncteur. Le procédé consiste à définir une référence de tension non nulle pour la tension secondaire, à envoyer des impulsions de déclenchement pour commander les commutateurs à semi-conducteurs des cellules de convertisseur, et à équilibrer les tensions de branche de phase des branches de phase au moyen de la tension résultant de la référence de tension définie sur le second côté du MMC.
PCT/EP2017/066524 2017-07-03 2017-07-03 Équilibrage de tension de convertisseur de courant WO2019007479A1 (fr)

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Application Number Priority Date Filing Date Title
PCT/EP2017/066524 WO2019007479A1 (fr) 2017-07-03 2017-07-03 Équilibrage de tension de convertisseur de courant

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP2017/066524 WO2019007479A1 (fr) 2017-07-03 2017-07-03 Équilibrage de tension de convertisseur de courant

Publications (1)

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WO2019007479A1 true WO2019007479A1 (fr) 2019-01-10

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Publication number Priority date Publication date Assignee Title
CN110350798A (zh) * 2019-06-27 2019-10-18 浙江大学 模块化多电平谐振变换器的桥臂间均压控制方法
CN110350798B (zh) * 2019-06-27 2020-10-23 浙江大学 模块化多电平谐振变换器的桥臂间均压控制方法
CN110798060A (zh) * 2019-09-24 2020-02-14 杭州电子科技大学 一种基于交错式分组的m3c预充电方法
CN112072933A (zh) * 2020-08-06 2020-12-11 清华大学 一种单向电流型模块化多电平换流器的电压平衡控制方法
CN113922682A (zh) * 2021-12-13 2022-01-11 四川大学 一种三相桥式电路直接级联型模块化多电平换流器
CN113922682B (zh) * 2021-12-13 2022-03-01 四川大学 一种三相桥式电路直接级联型模块化多电平换流器

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