EP3850740A1 - Procédé pour connecter un onduleur photovoltaïque (pv) à un réseau triphasé et onduleur pv - Google Patents

Procédé pour connecter un onduleur photovoltaïque (pv) à un réseau triphasé et onduleur pv

Info

Publication number
EP3850740A1
EP3850740A1 EP19812681.5A EP19812681A EP3850740A1 EP 3850740 A1 EP3850740 A1 EP 3850740A1 EP 19812681 A EP19812681 A EP 19812681A EP 3850740 A1 EP3850740 A1 EP 3850740A1
Authority
EP
European Patent Office
Prior art keywords
phase
output connection
network
potential
relay
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.)
Pending
Application number
EP19812681.5A
Other languages
German (de)
English (en)
Inventor
Harald Drangmeister
Michael Eberle
Leif Grundmann
Sven Meißinger
Gennadi Starobinski
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.)
Kaco New Energy GmbH
Original Assignee
Kaco New Energy GmbH
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 Kaco New Energy GmbH filed Critical Kaco New Energy GmbH
Publication of EP3850740A1 publication Critical patent/EP3850740A1/fr
Pending legal-status Critical Current

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
    • 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
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/381—Dispersed generators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/40—Synchronising a generator for connection to a network or to another generator
    • H02J3/44—Synchronising a generator for connection to a network or to another generator with means for ensuring correct phase sequence
    • 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
    • H02M7/53—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 using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—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 using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • H02M7/5387—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 using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/20—The dispersed energy generation being of renewable origin
    • H02J2300/22—The renewable source being solar energy
    • H02J2300/24—The renewable source being solar energy of photovoltaic origin
    • 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
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/125—Avoiding or suppressing excessive transient voltages or currents
    • 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
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/56—Power conversion systems, e.g. maximum power point trackers

Definitions

  • the PV inverter has a three-phase inverter unit fed from an intermediate circuit voltage, the three-phase inverter unit having a first output connection, a second output connection and a third output connection.
  • the three-phase inverter unit having a first output connection, a second output connection and a third output connection.
  • a typically used transformer of the three-phase network generates a voltage that is symmetrical to PE.
  • PV module strings from which the DC link voltage is obtained, typically have a very high-resistance connection to PE.
  • normal aging processes can result in insulation resistances down to 50 kOhm.
  • An insulation resistance of 50 kOhm is still part of the nominal operation. Insulation resistances that are less than 50 kOhm typically lead to an error message on the inverter.
  • an additional balancing circuit can be provided, for example, which compensates for the offset of the intermediate circuit before the inverter is coupled to the three-phase network.
  • so-called "inrush current relays” can also be used, which can carry the high current that occurs without being damaged.
  • both options mean additional circuit outlay and correspondingly increased production costs.
  • At least one phase relay is switched on in the "correct" half-wave, ie in a half-wave in which the output voltage can be set in such a way that it corresponds exactly to the phase voltage, so that no or only a very slight inrush current via the or the switched phase relay flows.
  • the offset is therefore compensated so quickly that the voltages of the other phases not yet connected to the three-phase network can be generated by the inverter without clipping, at the latest in the following half-phase. After that, as described above, it is ensured that the voltages generated by the inverter are sufficiently low Voltage difference to the corresponding phase voltages of the three-phase network are generated, the remaining relays can be closed without causing undesirably high currents through the relays. After grid synchronization has been successfully completed in this way, feed-in operation can be started.
  • the inverter can only generate either the positive or the negative half-wave plus the DC offset.
  • an output connection of the inverter can now first be galvanically connected to the associated mains phase of the three-phase network.
  • the phase relay that closes first is switched on in the half-wave in which the inverter can also set the necessary phase voltage.
  • the DC link offset can be reduced without current peaks, so that the remaining phase relays can then be closed without any problems, since the inverter can now set the necessary voltage at the associated output connections in any case.
  • the PV inverter 1 conventionally has a three-phase inverter unit 3 fed from an intermediate circuit voltage UDC, which is connected via relay-side relays 11, 12 and 13 to an output filter 14 or is ver bindable.
  • the output filter 14 has the task of smoothing the phase signals provided by the inverter unit 3, so that at least approximately sinusoidal signals are generated.
  • the output filter 14 can, for example, have star-shaped capacitors and / or each of the three phases of inductors connected in series.
  • the relays 11, 12 and 13 and the output filter 14 are included in the further description of the three-phase inverter unit 3 and were only extracted from this for the purpose of illustration.
  • a possible voltage setting range of the inverter unit 3 at the first output connection 4, at the second output connection 5 and at the third output connection 6 in a state not connected to the three-phase network 2 is from a potential difference between the positive intermediate circuit potential UDC + and a protective earth (PE ) - Potential and a potential difference between the negative DC link potential UDC and the PE potential.
  • PE protective earth
  • control unit 10 Before connecting the inverter unit 3 to the grid phases U, V, W by closing the phase relays 7, 8, 9, the control unit 10 carries out the steps described below.
  • a voltage can be set and adjusted which corresponds to the voltage on the associated mains phase U, V or W during a half phase. If two of the three phase relays 7, 8 and 9 meet this condition, both can
  • Phase relays are closed or, for example, only those phase relays are closed whose voltage setting range is closest to the necessary voltage of the mains phase.
  • the DC link offset quickly compensates for itself due to the low-impedance connection to the phase symmetrical about PE, for example in 2 to 5 milliseconds, preferably in about 3 milliseconds.
  • the dimensioning of the output filter can be carried out accordingly, on the one hand to keep the compensating currents that occur due to the reduction in the offset of the DC link at an acceptable level, and on the other hand to be able to ensure that the inverter already receives the voltages in the next half phase for all inverter outputs without clipping.
  • the exemplary embodiment of the invention shown in FIG. 1 has voltage measuring devices 15, 16 and 17 connected to the input side of the output filter 14.
  • the voltage measuring devices 15 to 17 can also be connected elsewhere, for example at the outputs of the output filter 14 or on the other side of the relays 11, 12 and 13 on the inverter side.
  • Amplitude and respective phase position of the phases U, V, W of the three-phase network 2 can be determined.
  • These voltage measuring devices 15 to 20 are usually hen with corresponding PV generators according to the prior art, so that the invention does not require any additional circuitry here either.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Inverter Devices (AREA)

Abstract

L'invention concerne un procédé pour faire fonctionner un onduleur photovoltaïque (PV) (1) et un onduleur PV (1). Les relais de phase (7, 8, 9) de l'onduleur PV (1) ne sont pas fermés simultanément lors de la connexion électrique de l'onduleur PV (1) à un réseau triphasé (2). Au lieu de cela, seul est fermé le relais de phase (7, 8, 9) où une tension correspondant à la tension au niveau de la phase de réseau (U, V, VV) correspondante peut être régulée ou est régulée au niveau du raccordement de sortie (4, 5, 6) correspondant.
EP19812681.5A 2018-11-12 2019-11-08 Procédé pour connecter un onduleur photovoltaïque (pv) à un réseau triphasé et onduleur pv Pending EP3850740A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102018219273.1A DE102018219273A1 (de) 2018-11-12 2018-11-12 Verfahren zum Betreiben eines Photovoltaik(PV)-Wechselrichters und PV-Wechselrichter
PCT/EP2019/080682 WO2020099263A1 (fr) 2018-11-12 2019-11-08 Procédé pour connecter un onduleur photovoltaïque (pv) à un réseau triphasé et onduleur pv

Publications (1)

Publication Number Publication Date
EP3850740A1 true EP3850740A1 (fr) 2021-07-21

Family

ID=68731935

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19812681.5A Pending EP3850740A1 (fr) 2018-11-12 2019-11-08 Procédé pour connecter un onduleur photovoltaïque (pv) à un réseau triphasé et onduleur pv

Country Status (3)

Country Link
EP (1) EP3850740A1 (fr)
DE (1) DE102018219273A1 (fr)
WO (1) WO2020099263A1 (fr)

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006022686B4 (de) * 2006-05-16 2018-03-15 Sma Solar Technology Ag Messanordnung zur Ermittlung des Isolationswiderstandes einer elektrischen Vorrichtung oder einer Anlage
DK176983B1 (en) * 2008-11-07 2010-09-20 Danfoss Solar Inverters As Photovoltaic power plant
DE102011055220B4 (de) * 2011-11-10 2017-02-09 Sma Solar Technology Ag Zuschalten eines Wechselrichters in einem Solarkraftwerk mit verschobenem Potentialmittelpunkt
WO2014203091A1 (fr) * 2013-06-18 2014-12-24 Sma Solar Technology Ag Procédé et agencement pour l'égalisation active de potentiels de référence avant le raccordement au réseau d'une installation photovoltaïque
EP2963760A1 (fr) * 2014-06-30 2016-01-06 SMA Solar Technology AG Compensation de potentiel à la terre pour système de génération d'énergie photovoltaïque
TWI542114B (zh) * 2015-06-17 2016-07-11 台達電子工業股份有限公司 太陽能逆變器並網系統及三相並網方法
WO2017162892A1 (fr) * 2016-03-22 2017-09-28 Ingeteam Power Technology, S.A. Symétrisation du courant cc pour éliminer les perturbations du courant en mode commun pendant le branchement d'un inverseur photovoltaïque

Also Published As

Publication number Publication date
DE102018219273A1 (de) 2020-05-14
WO2020099263A1 (fr) 2020-05-22

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