WO2013174420A1 - Injection de courant dans un onduleur à deux niveaux connecté en cascade - Google Patents

Injection de courant dans un onduleur à deux niveaux connecté en cascade Download PDF

Info

Publication number
WO2013174420A1
WO2013174420A1 PCT/EP2012/059511 EP2012059511W WO2013174420A1 WO 2013174420 A1 WO2013174420 A1 WO 2013174420A1 EP 2012059511 W EP2012059511 W EP 2012059511W WO 2013174420 A1 WO2013174420 A1 WO 2013174420A1
Authority
WO
WIPO (PCT)
Prior art keywords
phase
voltage
vsc
terminal
harmonics
Prior art date
Application number
PCT/EP2012/059511
Other languages
English (en)
Inventor
Frans Dijkhuizen
Alireza NAMI
Georgios Demetriades
Original Assignee
Abb Research 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 Abb Research Ltd filed Critical Abb Research Ltd
Priority to PCT/EP2012/059511 priority Critical patent/WO2013174420A1/fr
Publication of WO2013174420A1 publication Critical patent/WO2013174420A1/fr

Links

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
    • 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
    • H02M1/12—Arrangements for reducing harmonics from ac input or output

Definitions

  • the invention disclosed herein generally relates to a cascaded multilevel voltage source converter (VSC) configured to convert DC voltage into AC voltage or vice versa. More precisely, the invention relates to a VSC comprising an active filter acting as a harmonics compensator suitable for reducing or removing harmonics in the AC output, in particular the harmonic at twice the fundamental AC frequency.
  • VSC cascaded multilevel voltage source converter
  • a VSC is a controllable voltage source, with an input connected to at least one capacitor functioning as a DC voltage source. At the outputs, the converter is operable to create a variable AC voltage. This is achieved by connecting the voltages of the capacitor or capacitors directly to any of the converter outputs using switches in the VSC.
  • PWM pulse- width modulation
  • the input DC voltage is normally kept constant when creating output voltage waveforms that are sinusoidal on average. The amplitude, the frequency and the phase of the AC voltage can be controlled by changing the switching pattern.
  • Multilevel converters are used in order to reduce harmonic distortion in the output of VSCs.
  • a multilevel converter is a converter with power semiconductor switches in each phase leg, which are switched in such a way that the output voltage(s) can assume several discrete levels.
  • VSCs may be equipped with converter regulating components configured to regulate a circulating current flowing through the phase legs and perturbing the output AC voltage, e.g., by introducing cell ripple.
  • the circulating current closes between the phase legs but does not enter the AC grid through the AC phase terminal(s).
  • Appropriate regulation of the circulating current improves the quality of the VSC for a given switching pattern. Conversely, such regulation may allow a simpler and more economical switching pattern to be used.
  • the ratio of the switching frequency, at which the switching modules are operated to provide an approximately sinusoidal AC output, and the frequency of the AC output itself - the pulse number - is an important figure of merit for a VSC and may be between 3 and 4 in state-of-the art equipment. It is generally speaking desirable to reduce the pulse number further, but absent suitable compensation this happens at the price of less favourable energy efficiency and decreased stability and/or controllability of the system.
  • WO2008/067785 and WO201 1/000428 disclose two different techniques for regulating the circulating current. According to the first document, the regulation is achieved by modifying the control pattern applied to the switching modules.
  • the second documents proposes an actively controlled harmonics compensator connected via a coupling inductor arranged in series with a phase leg; this compensator may be of the current- stiff or voltage-stiff type.
  • the present invention has been made in view of the above limitations of the prior art. Hence, it is an object of the invention to provide a multilevel VSC in which the amplitude of the second-order harmonics is reduced.
  • Another object is to enable a further reduction of the cell switching frequency (or pulse number) without significant deterioration of the output voltage from the VSC.
  • a further object is to enable such switching frequency reduction while maintaining good cell balancing.
  • a still further object is to improve the conversion efficiency of the VSC.
  • the invention provides a multilevel VSC with the features set forth in claim 1 .
  • a multilevel VSC is adapted to convert DC voltage into AC voltage (or vice versa).
  • the DC voltage is applied (or output) at a first and second DC terminal, and the AC voltage is output (or applied) at two or more AC phase terminals, depending on the number of AC voltage phases.
  • the DC voltage side is a source side and the AC voltage side is a load side.
  • the DC terminals may be provided in the form of bus bars.
  • the VSC is structured into phase legs extending parallel to one another between the DC terminals.
  • Each phase leg comprises at least:
  • the switching modules are preferably arranged in series. Preferably, there is an equal number of switching modules on either side of the AC phase terminal in the phase leg.
  • the harmonics compensator may be controlled by instructions according to per se known techniques for reducing the circulating current; for example, as will be discussed in detail below, the control instructions may cause the harmonics compensator to cancel or partially attenuate a circulating current, the waveform of which has a frequency of about twice the fundamental frequency of the AC voltage in the VSC.
  • the harmonics compensator is provided in the form of at least one active filter configured to inject current into the phase leg.
  • the active filter may include at least one externally powered amplifier.
  • the ability to introduce current carrying a positive net energy into the load side of the converter provides for greater freedom to regulate the injected current, so that the attenuation or cancelling of the circulating current may become more efficient.
  • the response of the active filter may instead be controlled in accordance with a frequency-dependent transfer function in terms of magnitude and/or phase.
  • the active filter comprises at least one low-voltage VSC.
  • the rating of the low-voltage VSC may be less than 10 per cent, preferably less than 5 per cent, than the total converter rating.
  • the circulating current is typically of much smaller amplitude than the output AC current, such low-voltage VSC may successfully control the circulating current while remaining itself a relatively affordable hardware component.
  • the active filter is preferably of wide-band type. More precisely, efficient control of the harmonics may require the low-voltage VSC to operate at a high switching frequency (e.g., with a pulse number in the conventional range). Since the harmonics control however may mitigate the influence of the second harmonic to a sufficient extent that the pulse number of the high- voltage-rated main multilevel VSC may be reduced, the invention still represents a potential saving in terms of manufacturing costs, bulkiness etc.
  • the harmonics compensator is connected to inject current between the AC phase terminal and the first plurality of switching modules.
  • the harmonics compensator is connected between the AC phase terminal and the second plurality of switching modules.
  • the harmonics compensator is connected to the phase leg via a current transformer, which is serially connected in the phase leg.
  • the harmonics compensator is magnetically coupled to the phase leg.
  • This connection type is advantageous in that galvanic isolation is achieved. Further, since a voltage transformation takes place, the high- voltage circuitry in the multilevel converter is separated from the harmonics compensator, allowing this to have a reduced voltage rating.
  • the harmonics compensator is connected in shunt, e.g., in parallel with a passive element in the phase leg.
  • the passive element is preferably a coupling inductor.
  • the harmonics compensator is galvanically connected to the phase leg. This connection type is
  • the harmonics compensator is connected in series in the AC phase terminal.
  • the active filter is powered from a source side (or primary side) of the VSC. In the special case of a VSC converting DC voltage into AC voltage, the active filter receives a positive net power from the DC voltage. Because the active filter injects current on the AC side, it supplies a positive net power to the AC side. It is understood, however, that the active filter may temporarily experience time periods during which the momentary power to or from the AC side or DC side is opposite in relation to the net power.
  • the active filter is a voltage source converter configured to output a voltage significantly smaller than the output voltage of the multilevel VSC, in which the active filter is arranged.
  • the output voltage of the active filter may be at most 10 % of the multilevel VSC design voltage; preferably, it is at most 5 % of the multilevel VSC design voltage.
  • figure 1 shows a conventional multilevel VSC, exemplifying the range of devices to which the present invention may be applied;
  • figure 2 shows a detail of the multilevel VSC in figure 1 , wherein AC, DC and circulating currents have been indicated;
  • figure 3 is a time plot of currents arising in the multilevel VSC in figure 1 , namely an upper arm current, a lower arm current and a circulating current;
  • figure 4 shows a multilevel VSC, to which harmonics compensators according to an embodiment of the invention have been magnetically connected
  • figure 5 shows a multilevel VSC with harmonics compensators connected in shunt via passive elements
  • figure 6 shows an example active filter according to an example embodiment of the present invention
  • figure 7 is a conceptual drawing visualizing ideas related to harmonics compensation.
  • FIG. 1 a is a block diagram of a multilevel VSC 100, in which a DC voltage V dc is supplied via an upper 1 13 and a lower 1 14 bus bar (DC terminals) to three phase legs 120 arranged in parallel.
  • Each leg 120 comprises, in the order from the upper to the lower bus bar, a first plurality 1 10 of switching modules 101 , an upper phase inductor 1 1 1 , a branching point to an AC phase terminal 1 15, a lower phase inductor 1 12 and a second plurality 1 16 of switching modules 101 .
  • the portion of a phase leg 120 on either side of the AC phase terminal 1 15 may be referred to as an arm.
  • each plurality 1 10, 1 16 of switching modules may comprise a number of at least two serially connected switching modules 101 .
  • Each of the switching modules 101 may be a commutation cell according to one of the representative structures shown in figure 1 c.
  • each commutation cell may comprise a DC capacitor holding a direct voltage and two valves 103 implemented as semiconductor switching components, namely as at least one insulated gate bipolar transistor (IGBT), possibly equipped with a free-wheeling diode to form a reverse-conducting insulated gate bipolar transistor (RC-IGBT), a bi-mode insulated gate transistor (BIGT), a gate turn-off thyristor (GTO), an integrated gate commutated thyristor (IGCT) or a metal-oxide-semiconductor field-effect transistor (MOSFET).
  • IGBT reverse-conducting insulated gate bipolar transistor
  • BIGT bi-mode insulated gate transistor
  • GTO gate turn-off thyristor
  • IGCT integrated gate commutated thyristor
  • MOSFET metal-oxide-semiconductor field-effect transistor
  • the DC to AC conversion in the VSC 100 is achieved by operating the switching modules 101 in a coordinated manner over time, in response to signals provided from a controller 130 (e.g., optically or electrically) directly to the switching modules 101 or via sub-controllers (not shown) within each plurality 1 10, 1 16 of switching modules. This technique is well known in the art.
  • Figure 2 has a twofold purpose. First, it introduces notation for currents arising in a multilevel VSC 100 of the general type illustrated in figure 1 . While the thin solid lines indicate the underlying circuitry, the dash-dotted line (— ) indicates a DC current l d and portions thereof. The solid line (— )
  • figure 2 illustrates a conventional attempt to compensate undesirable harmonics in the phase voltage, namely by providing AC phase reactors comprising a passive notch-type filter 201 for reducing the second harmonic but essentially no other frequency components.
  • the notch-type filter 201 comprises two parallel branches of the phase terminal 1 15, each containing two serially arranged inductors 202, 203 and 205, 206. The midpoint between each pair of inductors are interconnected via a capacitor 207.
  • the capacitor 207 is arranged in parallel with a component 204 having a diode-like behaviour in the design voltage range and thereby serving as overvoltage protection.
  • the parallel component 204 may for instance be a varistor.
  • Figure 4 shows a multilevel VSC with harmonics compensators 401 .
  • the first compensator 401 which is associated with the first phase leg 120a, is configured to inject a compensating current i C ii .
  • a compensating current i C ii is configured to inject a compensating current i C ii .
  • compensator 401 may include a harmonics sensing means (not shown) for diagnosing the momentary state of the VSC - in particular the spectral content of the current flowing through each phase leg - and determining an appropriate corrective action to be taken in terms of compensating current i C ii .
  • the harmonics compensator 401 may be connected to the DC side of the VSC, from which it draws a relatively input power in periods where this is necessary. Since the injected current may contribute to the AC output of the VSC to a large extent, the action of the active filter in the harmonics compensator 401 may be regarded as a parallel path through which energy flows from the DC (source) side to the AC (load) side.
  • harmonics compensators 401 , 402, 403 are identical to the harmonics compensators 401 , 402, 403 .
  • the external controller may form part of the VSC and may be communicatively connected to one or more harmonics sensing means (not shown) and the harmonics compensators 401 , 402, 403.
  • the second (third) compensator 402 (403) is configured to inject a second (third) compensation current ⁇ c ⁇ 2 (id3) into the second phase leg in order to compensate a circulating current i C 2 (i C 3)-
  • the first, second and third harmonics compensators may be implemented in the VSC as a common compensator unit connected to each of the phase legs.
  • Figure 5 illustrates a further possible way of connecting harmonics compensators 401 , 402, 403 to a multilevel VSC 100 in shunt, namely, by galvanic connection across respective passive elements 501 a, 501 b, 501 c, as outlined in previous sections.
  • Figure 5 shows a VSC in which the passive elements are inductors.
  • the passive elements 501 a, 501 b, 501 c are located in the lower bus bar 1 14, that is, between respective second pluralities 1 16 of switching modules and the lower DC terminal V dc .
  • connection technique or a similar one may however be used to achieve current insertion at other locations of the VSC, such as between the AC phase terminal 1 15 and either of the first 1 10 and second 1 16 pluralities of switching modules.
  • a harmonics compensator may also be connected in shunt in the AC phase terminal 1 15.
  • Figure 6 shows an example active filter 401 , 402, 403 that may be used in embodiments of the present invention.
  • the active filter 401 , 402, 403 may be connected in series or in shunt; the particulars of each approach have been discussed above.
  • the active filter 401 , 402, 403 may be implemented as a single unit common to all phases, as shown in figure 6, or as one unit for each phase.
  • injection line 607 which connects the filter to a phase leg of the main VSC, comprises three
  • the three currents to be injected are produced in the active filter 401 , 402, 403 by a network 605 (e.g., VSC) of switching modules.
  • VSC voltage-to-dielectric
  • the switching modules are connected to a DC voltage V dc supplied via a DC capacitor 606. From the network 605, the currents are supplied to the phase leg via a filter inductor 604 and a step-down
  • the active filter 401 , 402, 403 - including its VSC - is separated from the high voltage in the phase leg, and may therefore carry a lower voltage rating without detriment.
  • the VSC in the active filter 401 , 402, 403 may be referred to as a low- voltage VSC within the main VSC.
  • the step-down transformer 603 may be provided as three separate transformers arranged in parallel.
  • the step-down transformer 603 may be a three-phase transformer with star-delta configuration.
  • one VSC system may be provided with an independent active filter (not shown) injecting current into each phase leg.
  • the three active filters in such a configuration may however, although they are separate units, receive control signals coordinated by a common control unit (not shown).
  • figure 7 illustrates one of the principles underlying the invention on a more conceptual level, without a strict connection to the actual implementations discussed above,
  • An idea underlying the invention is to effect a simple switching pattern in the main VSC to produce a basic signal with high amplitude.
  • the switching pattern may be simple in respect of its low pulse number, which would produce a discrete pattern (e.g., a square-like wave) in the absence of DC capacitors and other components temporarily storing and exchanging electric energy with the system.
  • a lower-amplitude compensation signal is added to the high-amplitude basic signal in order to approximate a desired sinusoidal signal, in which the fundamental frequency dominates.
  • Example waveforms of the basic signal, compensation signal and sinusoidal signal are illustrated, in this sequence, by the diagrams in figure 7.
  • a multilevel VSC may operate in rectifier mode, in which it converts AC power into DC power, without departing from the scope of the invention

Abstract

La présente invention concerne un onduleur formant source de tension multi-niveaux (100) configuré pour convertir une tension continue sur des première et seconde bornes de courant continu (113, 114) en une tension alternative sur des bornes de phase alternatives (115) ou inversement. Il comprend au moins deux branches de phase (120), chacune s'étendant entre les bornes de courant continu et comprenant une borne de phase alternative (115) et des première et seconde pluralités (110, 116) de modules de commutation (101) disposés entre la borne de phase alternative et l'une ou l'autre des bornes de courant continu. La branche de phase comprend en outre au moins un compensateur d'harmoniques apte à réduire les harmoniques présents dans un courant circulant dans la branche de phase, le compensateur d'harmoniques comprenant un filtre actif pouvant être mis en fonctionnement pour injecter un courant dans la branche de phase. Dans différents modes de réalisation, le compensateur d'harmoniques est agencé de telle manière qu'il injecte un courant dans la branche de phase ou dans la borne de phase alternative qu'elle comporte.
PCT/EP2012/059511 2012-05-22 2012-05-22 Injection de courant dans un onduleur à deux niveaux connecté en cascade WO2013174420A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/EP2012/059511 WO2013174420A1 (fr) 2012-05-22 2012-05-22 Injection de courant dans un onduleur à deux niveaux connecté en cascade

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP2012/059511 WO2013174420A1 (fr) 2012-05-22 2012-05-22 Injection de courant dans un onduleur à deux niveaux connecté en cascade

Publications (1)

Publication Number Publication Date
WO2013174420A1 true WO2013174420A1 (fr) 2013-11-28

Family

ID=46201579

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2012/059511 WO2013174420A1 (fr) 2012-05-22 2012-05-22 Injection de courant dans un onduleur à deux niveaux connecté en cascade

Country Status (1)

Country Link
WO (1) WO2013174420A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20210359619A1 (en) * 2016-11-16 2021-11-18 Schneider Electric Solar Inverters Usa, Inc. Interleaved parallel inverters with integrated filter inductor and interphase transformer

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008067785A1 (fr) 2006-12-08 2008-06-12 Siemens Aktiengesellschaft Dispositif pour transformer un courant électrique
WO2011000428A1 (fr) 2009-07-02 2011-01-06 Abb Technology Ag Convertisseur de puissance à sortie de tension à plusieurs niveaux et compensateur d'harmoniques
WO2011012436A2 (fr) * 2009-07-30 2011-02-03 Siemens Aktiengesellschaft Dispositif de compensation des oscillations harmoniques se produisant sur les chemins de courant d'un réseau à haute tension

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008067785A1 (fr) 2006-12-08 2008-06-12 Siemens Aktiengesellschaft Dispositif pour transformer un courant électrique
WO2011000428A1 (fr) 2009-07-02 2011-01-06 Abb Technology Ag Convertisseur de puissance à sortie de tension à plusieurs niveaux et compensateur d'harmoniques
WO2011012436A2 (fr) * 2009-07-30 2011-02-03 Siemens Aktiengesellschaft Dispositif de compensation des oscillations harmoniques se produisant sur les chemins de courant d'un réseau à haute tension

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
AKAGI H ED - EUROPEAN POWER ELECTRONICS AND DRIVES ASSOCIATION: "NEW TRENDS IN ACTIVE FILTERS", EPE '95: 6TH. EUROPEAN CONFERENCE ON POWER ELECTRONICS AND APPLICATIONS. SEVILLA, SEPT. 19 - 21, 1995; [EUROPEAN CONFERENCE ON POWER ELECTRONICS AND APPLICATIONS], BRUSSELS, EPE ASSOCIATION, B, vol. O, 19 September 1995 (1995-09-19), pages 17 - 26, XP000537486 *
K. LIVES ET AL.: "IECON 2011 - 37th Annual Conference on IEEE Industrial Electronics Society", THE PROCEEDINGS OF THIS MEETING
LENNART ANGQUIST ET AL: "Inner control of Modular Multilevel Converters - An approach using open-loop estimation of stored energy", 2010 INTERNATIONAL POWER ELECTRONICS CONFERENCE : IPEC-SAPPORO 2010 - [ECCE ASIA] ; SAPPORO, JAPAN, IEEE, PISCATAWAY, NJ, USA, 21 June 2010 (2010-06-21), pages 1579 - 1585, XP031729743, ISBN: 978-1-4244-5394-8 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20210359619A1 (en) * 2016-11-16 2021-11-18 Schneider Electric Solar Inverters Usa, Inc. Interleaved parallel inverters with integrated filter inductor and interphase transformer
US11588393B2 (en) 2016-11-16 2023-02-21 Schneider Electric Solar Inverters Usa, Inc. Interleaved parallel inverters with integrated filter inductor and interphase transformer

Similar Documents

Publication Publication Date Title
US10491098B2 (en) Soft switching solid state transformers and converters
She et al. AC circulating currents suppression in modular multilevel converter
US10224830B2 (en) System and method for controlling a back-to-back three-level converter with voltage ripple compensation
EP2727234B1 (fr) Convertisseur
EP3487058B1 (fr) Commutation efficace pour circuit convertisseur
KR101633049B1 (ko) 전력 변환 장치
JP5511947B2 (ja) マルチレベル電圧出力および高調波補償器を備える電力変換器
US8665617B2 (en) Plant for transmitting electric power
US20110019453A1 (en) Electric circuit for converting direct current into alternating current
US10177684B2 (en) Converter for an AC system
US20140049998A1 (en) DC to AC Power Converter
EP2961057A1 (fr) Convertisseur de source de tension et commande de celui-ci
CN105191108A (zh) 变换器
WO2017119977A2 (fr) Système et procédé d'intégration de stockage d'énergie dans un convertisseur de puissance modulaire
WO2013185825A1 (fr) Poste ccht multiligne à entrées mmc et csc
US10205407B2 (en) Inverter device, energy storage system and method of controlling an inverter device
CN113474986A (zh) 用于mmc的升降压换流器单元
US11152863B2 (en) Method for controlling extraction of power from multiple photo voltaic (PV) arrays and system thereof
EP3963703A1 (fr) Convertisseur électrique
EP2525483A1 (fr) Convertisseur de courant modulaire avec des accumulateurs d'énergie
WO2013174420A1 (fr) Injection de courant dans un onduleur à deux niveaux connecté en cascade
Udovichenko AC voltage regulators with high frequency transformer review
Asoodar et al. A new switching algorithm in Back to Back CHB Multilevel converters with the advantage of eliminating isolation stage
WO2012003857A1 (fr) Agencement d'interfaçage entre systèmes à courant alternatif et continu
Wang et al. Strategies for decoupling internal and external dynamics resulting from inter-arm passive component tolerances in HVDC-MMC

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: 12724928

Country of ref document: EP

Kind code of ref document: A1

DPE1 Request for preliminary examination filed after expiration of 19th month from priority date (pct application filed from 20040101)
NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 12724928

Country of ref document: EP

Kind code of ref document: A1