EP4244965A1 - Commutation d'un convertisseur ca/cc sur un réseau cc - Google Patents

Commutation d'un convertisseur ca/cc sur un réseau cc

Info

Publication number
EP4244965A1
EP4244965A1 EP21811302.5A EP21811302A EP4244965A1 EP 4244965 A1 EP4244965 A1 EP 4244965A1 EP 21811302 A EP21811302 A EP 21811302A EP 4244965 A1 EP4244965 A1 EP 4244965A1
Authority
EP
European Patent Office
Prior art keywords
converter
voltage
power converter
output voltage
llsym
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
EP21811302.5A
Other languages
German (de)
English (en)
Inventor
Alexander UNRU
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.)
SMA Solar Technology AG
Original Assignee
SMA Solar Technology 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 SMA Solar Technology AG filed Critical SMA Solar Technology AG
Publication of EP4244965A1 publication Critical patent/EP4244965A1/fr
Pending legal-status Critical Current

Links

Classifications

    • 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
    • H02J1/00—Circuit arrangements for dc mains or dc distribution networks
    • 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
    • H02M1/0067—Converter structures employing plural converter units, other than for parallel operation of the units on a single load
    • H02M1/007—Plural converter units in cascade
    • 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
    • H02J1/00—Circuit arrangements for dc mains or dc distribution networks
    • H02J1/10—Parallel operation of dc sources
    • H02J1/102—Parallel operation of dc sources being switching 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
    • H02J5/00—Circuit arrangements for transfer of electric power between ac networks and dc networks
    • 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
    • H02M1/0009—Devices or circuits for detecting current in 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
    • 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
    • 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
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static 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
    • H02M7/66—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with possibility of reversal
    • H02M7/68—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with possibility of reversal by static converters
    • H02M7/72—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/79—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with 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
    • H02M7/797—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with 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

Definitions

  • a DC energy system comprises at least one energy source that preferably makes electrical power available as direct current, i.e. a DC source, e.g. a battery, a PV generator or a fuel cell, and at least one load that preferably consumes electrical power as direct current. i.e. a DC sink, e.g. B. a consumer, and connections between these electrical components.
  • the DC power system may include a DC grid or bus where the electrical components are connected and may include other sources, storage, and/or loads. The transition between a DC bus with a few connected components, for example only one source and one sink, and a DC network with a large number of such components is fluid.
  • the term DC network is also understood to mean a DC bus.
  • Such a DC network can be grounded or ungrounded.
  • different monitoring and protection mechanisms may be required by standards in the event of a ground fault.
  • An unearthed DC network in which the potentials DC+ and DC- of the respective DC lines DCL+ and DCL- have no fixed reference to the earth potential, has the advantage that any first earth fault in the DC network, for example an insulation fault along one of the DC lines, still no harm.
  • insulation monitoring is required in order to detect the occurrence of any fault and, if necessary, to be able to initiate countermeasures in the event of a first ground fault, e.g. switch off the energy source or disconnect the energy source and/or the fault location from the DC network.
  • the potentials DC+ and DC- have a defined reference to the ground potential.
  • a ground reference can, for example, by means a resistive connection between the ground potential and one of the DC potentials DC+ or DC-.
  • a DC network can be connected to another energy network, e.g. B. another DC network or an AC network, for example an AC supply network, and exchange electrical power with the other energy network, in particular to support or recharge the DC source in the DC network.
  • the DC network can also be supplied permanently or at times completely with energy from the other energy network via the converter, with the energy source of the DC network being able to be used to buffer power fluctuations if necessary.
  • the DC network is automatically provided with a fixed earth reference via the power converter, i.e. grounded.
  • the concrete position of the potentials of the DC network relative to the ground reference is specified by the concrete topology of the power converter used.
  • the converter can have a divided intermediate circuit whose midpoint, ie, middle potential, is connected to a neutral conductor with a fixed ground reference, so that the DC potentials on the intermediate circuit are largely symmetrical about ground potential.
  • a DC network that is not grounded per se also becomes a grounded network through a connection to a grounded energy network via a transformerless converter.
  • There can therefore be two operating states for such a DC network unearthed "stand-alone" operation and grounded operation when connected to the grounded energy network. This must be taken into account when designing the system.
  • DC direct current or direct current
  • AC alternating current
  • the invention is based on the object of demonstrating an electrical system and a method that enable safe operation of a DC energy system.
  • the object is solved by an electrical system having the features of independent patent claim 1 .
  • the object is solved by a method having the features of independent claim 13 .
  • Advantageous embodiments of the method are claimed in the dependent claims.
  • An electrical system has a power converter and a DC/DC converter, the power converter being set up for power transfer between an AC side of the power converter and a DC side of the power converter.
  • the AC side of the converter can be connected to a grounded three-phase AC supply network and the DC side of the converter can be connected to an ungrounded DC network.
  • the converter has a bridge circuit whose AC connections can be connected to the AC side of the converter via AC relays and whose DC connections can be connected to the DC side of the converter via disconnectors, with the DC/DC controller being an output side has, which faces the DC side of the converter.
  • the electrical system has a measuring device that is set up to measure a DC converter voltage and a DC/DC output voltage present on the output side of the DC/DC converter, the DC Converter voltage and the DC/DC output voltage are on opposite sides of the disconnect switches.
  • the electrical system has a control unit that is set up to control the DC/DC converter in such a way that a DC/DC output voltage is set on the output side of the DC/DC converter, the magnitude of which corresponds to the DC converter voltage.
  • this enables a variable connection of an ungrounded DC network to a grounded AC supply network, e.g. B. via a transformerless converter without having to change the DC-side protection concept.
  • Residual current sensors could trigger.
  • the output side of the DC/DC converter is the side that faces the DC side of the power converter.
  • a voltage is initially present on an input side of the DC/DC controller, in particular due to a DC intermediate circuit of the converter or another DC source in the DC network, for example a battery.
  • the voltage on the output side of the DC/DC converter is the DC/DC output voltage.
  • the output side is the one on which the voltage can be adjusted by the DC/DC converter relative to the given voltage on the input side of the DC/DC converter.
  • the level of the voltages can be adjusted, for example, in such a way that the DC/DC controller is arranged inside the power converter and the DC/DC output voltage is set by the DC/DC controller on the side of the isolating switch on which the bridge circuit is located.
  • the level of the voltages can also be adjusted, for example, in such a way that the DC/DC controller is arranged in the DC network and the DC/DC output voltage is set by the DC/DC controller on the isolating switch side, that of the bridge circuit opposite.
  • the magnitude of the voltages means the voltage between the DC lines of the DC network or the voltage between the flow converter-side connections of the isolating switch. This corresponds to a difference in the potentials of the two DC lines of the DC network or the converter-side connections of the isolating switch.
  • the DC/DC output voltage is set to this amount of voltage.
  • the output side of the DC/DC converter is connected to the DC side of the power converter.
  • the DC/DC converter can be arranged in particular within the power converter between the bridge circuit and the isolating switches.
  • the DC/DC converter generates the DC/DC output voltage by suitable clocking from an intermediate circuit voltage of the power converter.
  • the output side of the DC/DC converter can then be connected to the DC side of the power converter via the isolating switch, with the isolating switch being arranged outside the power converter.
  • the DC/DC converter in particular also be arranged outside the converter in the DC network.
  • the DC / DC controller in this embodiment DC/DC output voltage e.g. B. generate by appropriate clocking from a DC energy storage in the DC network, z. B. from a battery.
  • the output side of the DC/DC converter is then connected to the DC side of the power converter and the isolating switches are arranged between the DC/DC converter and the bridge circuit.
  • the isolating switches can be arranged either inside or outside the converter between the bridge circuit and the DC side of the converter.
  • the DC/DC output voltage is adjustable on the output side of the DC/DC converter and the DC converter voltage is on the opposite side of the disconnect switches from the DC/DC converter.
  • the measuring device is set up to determine the DC converter voltage and the DC/DC output voltage by measuring the voltages on the respective DC lines or connections to ground potential, with one DC line each via the isolating switch can each be connected to a DC connection. This means that each of the DC lines can be measured individually against ground potential.
  • control unit is set up to control the DC/DC converter in such a way that the respective voltages against ground potential of the DC converter voltage and the DC/DC output voltage are matched to one another.
  • position of the stresses is also adjusted in this embodiment, i. H. in addition to the amount, the position of the potentials of the DC lines or the DC connections to each other and in relation to a third point, e.g. B. to ground potential.
  • the control unit is set up to close the isolating switches when the DC/DC output voltage corresponds to the DC converter voltage. This enables the voltages to be equalized before the DC grid is connected and can avoid excessive equalizing currents when and after the isolating switches are closed.
  • the DC/DC output voltage corresponds to the DC converter voltage and these together form a DC bus voltage of the DC grid when the circuit breakers are closed.
  • the DC grid is inherently ungrounded, but is grounded via the converter and the grounded AC supply grid when the disconnectors are closed and the AC relays are also closed.
  • the power converter is able to precisely influence and control the DC voltages and, if necessary, their position in relation to the ground potential. This can improve the safety of the operation.
  • control unit is set up to control the DC/DC converter in such a way that the DC bus voltage is balanced, the balancing being carried out in particular around ground potential as the mid-potential. If the power converter is connected to the DC grid, it can influence the voltage in the DC grid. Balancing around ground potential offers advantages, since the highest voltage of the DC lines in the DC network against ground potential can be kept lower than the voltage between the DC lines in the DC, which simplifies the design and helps to improve safety.
  • control unit is set up to set the DC/DC output voltage on the output side of the DC/DC controller by clocking a symmetrical DC voltage converter.
  • the DC/DC controller is designed as a symmetrical DC voltage converter.
  • control unit is set up to connect the AC connections of the bridge circuit to the AC side of the power converter via AC relays and then to set the DC/DC output voltage.
  • the power converter is connected to the AC supply network before the DC/DC converter adjusts its DC/DC output voltage.
  • the AC connections and the DC connections of the bridge circuit are galvanically coupled and the The power transfer path between the AC side and the DC side of the power converter is in particular designed without a transformer.
  • an AC supply network with ground reference e.g. B. a grounded TN or TT network
  • an intermediate circuit voltage of such a transformerless and thus galvanically coupled power converter - after connection to the AC supply network - is approximately symmetrical about ground potential.
  • high compensating currents would arise, particularly if the asymmetry is caused by insulation faults in the DC network.
  • Such equalizing or fault currents can be avoided or even compensated for by the electrical system by balancing the DC bus voltage around ground potential.
  • a method for operating an electrical system with a power converter and a DC/DC converter in a DC network, the power converter being set up for power transfer between an AC side of the power converter and a DC side of the power converter, has the following steps:
  • the DC/DC output voltage can also be measured.
  • the magnitude of the voltages means the voltage between the DC lines of the DC network or the voltage between the flow converter-side connections of the isolating switch. This corresponds to a difference in the potentials of the two DC lines of the DC network or the converter-side connections of the isolating switch.
  • the DC/DC output voltage is set to this amount of voltage.
  • the DC power converter voltage and the DC/DC output voltage are determined by measuring the voltages on the respective DC lines or connections to ground potential, with each DC line being able to be connected to a respective DC connection via the isolating switch . This means that each of the DC lines can be measured individually against ground potential.
  • the respective voltages against ground potential of the DC converter voltage and the DC/DC output voltage are matched to one another.
  • the position of the stresses is also adjusted in this embodiment, i. H. in addition to the amount, the position of the potentials of the DC lines or the DC connections to each other and in relation to a third point, e.g. B. to ground potential.
  • One embodiment of the method has the step that, after the DC/DC output voltage has been set, the output side of the DC/DC converter is connected to the power converter by closing the isolating switch.
  • An embodiment of the method comprises the step of connecting the AC terminals of the bridge circuit to the AC side of the power converter via AC relays before the DC/DC output voltage is adjusted.
  • One embodiment of the method has the step that after the isolating switch has been closed, the DC/DC controller carries out a balancing of the DC bus voltage, the DC/DC output voltage corresponding to the DC converter voltage and these together forming a DC bus voltage of the form the DC grid when the circuit breakers are closed.
  • the DC grid is inherently ungrounded, but is grounded via the AC utility grid when the disconnect switches are closed and the AC relays are also closed.
  • the balancing is carried out in particular around the ground potential as the middle potential.
  • FIG. 1 schematically shows an embodiment of an electrical system
  • 3 schematically shows an exemplary embodiment of a method
  • 4 schematically shows possible courses of voltages.
  • FIG. 1 an embodiment of an electrical system is shown schematically.
  • a power converter 10 has an AC side 16 and a DC side 18 .
  • a three-phase AC supply network 12 grounded at ground potential PE is connected to the AC side 16 .
  • a battery 42 can be connected to the DC grid 14 via DC switches 46 .
  • a load 44 can be connected to the DC grid via DC switches 48 .
  • the load 44 can in particular include one or more consumers such.
  • the battery 42 and the load 44 are connected to the power converter 10 via DC lines DC+, DC-.
  • the power converter 10 has a bridge circuit 20 which is designed to convert alternating current or alternating voltage at AC terminals ACL1, ACL2, ACL3 into direct current or direct voltage at DC terminals DCL+, DCL+.
  • the bridge circuit 20 is also designed to convert direct current or direct voltage at the DC terminals DCL+, DCL+ into alternating current or alternating voltage at the AC terminals ACL1, ACL2, ACL3.
  • the conversion takes place in that a control unit 30 suitably controls the semiconductor switch of the bridge circuit 20 .
  • the bridge circuit 20 with semiconductor switches is generally designed without a transformer, ie the AC terminals ACL1, ACL2, ACL3 and the DC terminals DCL+, DCL- of such a bridge circuit are galvanically coupled.
  • the DC connections DCL +, DCL- are thus automatically grounded via the bridge circuit 20 in regular operation of the power converter 10 .
  • the DC lines DC+, DC- are connected to the DC terminals DCL+, DCL-.
  • the concrete position of the potentials of the DC lines relative to the ground reference (DC+/DC- to PE) are specified by the topology of the bridge circuit 20 that is actually used.
  • the bridge circuit 20 can have a DC-side, divided DC intermediate circuit, the center point of which is connected to the neutral conductor of the AC supply network 12 with a fixed earth reference PE as the center potential, so that the DC potentials in the DC intermediate circuit and thus to the Adjust the DC connections DCL+, DCL- largely symmetrically around the earth potential PE.
  • a DC network 14 that is not grounded per se also becomes a grounded DC network 14 through a connection to the grounded AC supply network 12 via the transformerless converter 10.
  • the AC connections ACL1 , ACL2 , ACL3 can be connected to the AC side 16 and thus the bridge circuit 20 to the AC grid 12 via AC relays 22 .
  • the power converter 10 also has a fault current measurement 32 at the AC connections ACL1, ACL2, ACL3, which is based on a residual current measurement of the three AC connections ACL1, ACL2, ACL3.
  • the power converter 10 has a DC/DC converter 40, the input side of which is connected to the DC terminals DCL+, DCL- of the bridge circuit 20.
  • the DC/DC converter 40 can be used to generate a DC/DC output voltage Usym at an output side 24 of the DC/DC converter 40 relative to the voltage at the DC terminals DCL+, DCL-.
  • the DC/DC output voltage Usym can be set, for example, by the control unit 30 driving semiconductor switches of the DC/DC converter 40 . .
  • the output side 24 of the DC/DC converter 40 can be connected to the DC side 18 via isolating switches 26.1, 26.2.
  • a positive DC line DC+ of the DC network 14 is connected to the isolating switch 26.1 and a negative DC line DC- of the DC network 14 is connected to the isolating switch 26.2. tied together.
  • a measuring device 38 is set up measure the DC/DC output voltage llsym and/or a power converter voltage LIDCS ZU.
  • the power converter voltage LIDCS is present on the DC side 18 of the power converter 10, ie on the isolating switches 26.1, 26.2 on the side opposite the DC/DC converter 40.
  • FIG. 2 A further embodiment of the electrical system is shown schematically in FIG. 2 .
  • the power converter 10 has the AC side 16 and the DC side 18 .
  • the three-phase AC supply network 12 grounded at the ground potential PE is connected to the AC side 16 .
  • the battery 42 can be connected to the DC grid 14 via a DC switch 46 .
  • the load 44 can be connected to the DC grid via a DC switch 48 .
  • the load 44 can in particular include one or more consumers such. B. a machine, an industrial plant, or an electrolyser.
  • the battery 42 and the load 44 are connected to the power converter 10 via the DC lines DC+, DC-.
  • the power converter 10 has the bridge circuit 20, which is designed to convert alternating current or alternating voltage at AC terminals ACL1, ACL2, ACL3 into direct current or direct voltage at DC terminals DCL+, DCL+.
  • the bridge circuit 20 is also designed to convert direct current or direct voltage at the DC terminals DCL+, DCL+ into alternating current or alternating voltage at the AC terminals ACL1, ACL2, ACL3.
  • the conversion takes place in that the control unit 30 suitably controls the semiconductor switch of the bridge circuit 20 .
  • the bridge circuit 20 with semiconductor switches is usually designed without a transformer, i. H. the AC connections ACL1, ACL2, ACL3 and the DC connections DCL+, DCL- of such a bridge circuit are galvanically coupled. If the AC supply network has an earth reference, e.g. B. by a grounded to PE neutral conductor, the DC connections DCL +, DCL- are thus automatically grounded via the bridge circuit 20 in regular operation of the power converter 10 .
  • the DC lines DC+, DC- are connected to the DC terminals DCL+, DCL-.
  • the concrete position of the potentials of the DC lines relative to the ground reference (DC+/DC- to PE) are specified by the topology of the bridge circuit 20 that is actually used.
  • the bridge circuit 20 DC have a DC-side, split DC link whose center point is connected to the neutral conductor of the AC supply network 12 with a fixed ground reference PE as the middle potential, so that the DC potentials on the DC link and thus on the DC terminals DCL+ , Set DCL largely symmetrically around the earth potential PE.
  • a DC network 14 that is not grounded per se also becomes a grounded DC network 14 through a connection to the grounded AC supply network 12 via the transformerless converter 10.
  • the AC connections ACL1 , ACL2 , ACL3 can be connected to the AC side 16 and thus the bridge circuit 20 to the AC grid 12 via AC relays 22 .
  • the power converter 10 also has the residual current measurement 32 at the AC terminals ACL1, ACL2, ACL3, which is based on a residual current measurement of the three AC terminals ACL1, ACL2, ACL3.
  • the DC/DC converter 40 is arranged in the DC network 14 and to this extent outside of the power converter 10 .
  • the input side of the DC/DC converter 40 is connected to the battery 42 .
  • the DC/DC output voltage llsym can be set relative to the voltage of the battery 42.
  • the DC/DC output voltage llsym can be set, for example, by the control unit 30 driving semiconductor switches of the DC/DC converter 40 .
  • the DC connections DCL+, DCL- of the bridge circuit 20 can be connected to the DC side 18 via isolating switches 26.1, 26.2.
  • a positive DC line DC+ can be connected to the DC side 18 via the isolating switch 26.1 and a negative DC line DC- can be connected via the isolating switch 26.2. connected to the DC side.
  • a measuring device 38 is set up to measure the DC/DC output voltage llsym and/or a converter voltage LIDCS ZU.
  • the power converter voltage LIDCS is present on the DC side 18 of the bridge circuit 20, ie on the isolating switches 26.1, 26.2 on the side opposite the DC/DC converter 40. In the illustrated embodiment is the Converter voltage LIDCS thus at the DC terminals DCL +, DCL - the bridge circuit 20 of the converter 10 at.
  • FIG. 3 An exemplary embodiment of a method for operating the electrical system is shown schematically in FIG. 3 .
  • step S1 the AC terminals ACL1, ACL2, ACL3 of the bridge circuit 20 are connected to the AC side 16 of the power converter 10 via the AC relay 22.
  • the DC converter voltage llsym is measured.
  • the DC/DC output voltage llsym can also be measured in step S2.
  • the DC/DC output voltage llsym can be set on the output side 24 of the DC/DC controller 40, with the DC converter voltage LIDCS and the DC/DC output voltage llsym being present on opposite sides of the isolating switches 26.1, 26.2.
  • the DC converter voltage LIDCS and/or the DC/DC output voltage llsym can be determined by measuring the voltages on the respective DC lines DC+, DC or DC terminals DCL+, DCL+ against ground potential PE. This means that each of the DC lines DC+, DC- or the DC connections DCL+, DCL+ can be measured individually against ground potential PE.
  • a step S3 the DC/DC output voltage llsym is adjusted on the output side 24 of the DC/DC converter 40 such that the set DC/DC output voltage llsym is adjusted to the measured DC converter voltage LIDCS.
  • the respective voltages against ground potential PE of the DC converter voltage LIDCS and the DC/DC output voltage llsym can be matched to one another. The stresses are adjusted to each other in magnitude and position. Step S3 is repeated until the two voltages are equalized.
  • Step S4 is carried out when the equalization of the voltages succeeds.
  • step S4 after the DC/DC output voltage Usym has been set, the output side 24 of the DC/DC converter 40 is switched off by closing the isolating switch 26.1, 26.2 is connected to the DC side 18 of the power converter 10 at a point in time ts (FIG. 4).
  • the DC/DC converter 40 carries out a balancing of the DC bus voltage after the isolating switches 26.1, 26.2 have been closed, the balancing being carried out in particular around the earth potential as the middle potential.
  • Fig. 4 the profile of the DC converter voltage LIDCS and the DC/DC output voltage Isym is shown schematically as an example. Both voltages are shown in relation to the earth potential PE.
  • the top line in the graphs shows the potential of the plus DC line DC+ or the plus DC connection DCL+ relative to ground potential PE and the bottom line shows the potential of the minus DC line DC- or minus DC -connection DCL- to earth potential PE.
  • the DC converter voltage UDCS and the DC/DC output voltage Usym are independent of one another and have different values.
  • the DC/DC output voltage Usym is then adjusted to the DC converter voltage UDCS in terms of magnitude and position relative to ground potential PE. This is preferably done after the AC relay 22 has been closed and by activating the semiconductor switches of the DC/DC controller 40.
  • the control unit 30 is preferably used for the activation.
  • the isolating switches 26.1 and 26.2 are closed. If the isolating switches 26.1, 26.2 are closed, the DC/DC output voltage Usym corresponds to the DC converter voltage UDCS, and these together form a DC bus voltage of the DC network 14.
  • the DC network 14 is ungrounded per se when the isolating switches 26.1 are closed , 26.2 and likewise closed AC relay 22, however, are grounded via the converter 10 and the AC supply network 12.
  • the DC bus voltage is balanced by the DC/DC converter 40 or by the power converter 10, controlled by the control unit 30.
  • the upper voltage value is brought up to a desired positive DC bus voltage UBUS+ and the lower one Voltage value brought to a desired negative DC bus voltage LIBUS-.
  • the desired positive DC bus voltage UBUS+ and the desired negative DC bus voltage LIBUS- are preferably the same in magnitude and position relative to ground potential PE and are therefore symmetrical to ground potential PE.
  • the DC bus voltage is thus balanced with the ground potential PE.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Direct Current Feeding And Distribution (AREA)
  • Inverter Devices (AREA)
  • Emergency Protection Circuit Devices (AREA)

Abstract

L'invention concerne un système électrique qui comprend un convertisseur de puissance (10) et un convertisseur CC-CC (40), le convertisseur de puissance (10) étant conçu pour un transfert de puissance entre un côté CA (16) du convertisseur de puissance (10) et un côté CC (18) du convertisseur de puissance (10), le côté CA (16) du convertisseur de puissance (10) pouvant être connecté à un système d'alimentation électrique CA (12) triphasé mis à la terre et le côté CC (18) du convertisseur de puissance (10) pouvant être connecté à un réseau CC (14) non mis à la terre. Le convertisseur de puissance (10) comprend un circuit en pont (20), dont les bornes CA (ACL1, ACL2, ACL3) peuvent être connectées au côté CA (16) du convertisseur de puissance (10) par l'intermédiaire d'un relais CA (22), et dont les bornes CC (DCL+, DCL-) peuvent être connectées au côté CC du convertisseur de puissance (10) par l'intermédiaire de sectionneurs (26.1, 26.2). Le convertisseur CC-CC (40) comprend un côté sortie (24) qui est orienté vers le côté CC (18) du convertisseur de puissance (10), et le système électrique comprend un dispositif de mesure (38) qui est conçu pour mesurer une tension de convertisseur de puissance CC (UDCS) et une tension de sortie CC-CC (USym) appliquée au côté sortie (24) du convertisseur CC-CC (40), la tension de convertisseur de puissance CC (UDCS) et la tension de sortie CC-CC (USym) étant appliquées sur des côtés opposés des sectionneurs (26.1, 26.2). Le système électrique comprend une unité de commande (30) qui est conçue pour actionner le convertisseur CC-CC (40) de façon qu'une tension de sortie CC-CC (USym) qui correspond à la valeur de la tension de convertisseur de puissance CC (UDCS) soit définie sur le côté sortie (24) du convertisseur CC-CC (40). L'invention concerne en outre un procédé pour faire fonctionner un système électrique.
EP21811302.5A 2020-11-12 2021-11-12 Commutation d'un convertisseur ca/cc sur un réseau cc Pending EP4244965A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102020129917.6A DE102020129917A1 (de) 2020-11-12 2020-11-12 Verfahren zum Betrieb eines Gleichspannungsnetzes und Stromrichter zur Verbindung eines Gleichspannungsnetzes mit einem Wechselspannungsnetz
PCT/EP2021/081547 WO2022101420A1 (fr) 2020-11-12 2021-11-12 Commutation d'un convertisseur ca/cc sur un réseau cc

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EP4244965A1 true EP4244965A1 (fr) 2023-09-20

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US (1) US20230283069A1 (fr)
EP (1) EP4244965A1 (fr)
JP (1) JP2023549105A (fr)
CN (1) CN116438723A (fr)
DE (1) DE102020129917A1 (fr)
WO (1) WO2022101420A1 (fr)

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DE102006014780A1 (de) 2006-03-29 2007-10-18 Schekulin, Ulrich Gleichstromsteller und Wechselrichter-Schaltungsanordnung
DE102009012928A1 (de) 2009-03-12 2010-09-16 Kostal Industrie Elektrik Gmbh Energiewandleranlage
DE102013111075B4 (de) 2013-10-07 2016-08-04 Sma Solar Technology Ag Verfahren und Wechselrichter zum Ermitteln eines Betriebszustands einer Photovoltaikanlage
JP2019129675A (ja) * 2018-01-26 2019-08-01 富士電機株式会社 無停電電源装置
DE102018116013B4 (de) 2018-07-02 2023-12-28 Sma Solar Technology Ag Energieerzeugungsanlage, Wechselrichter und Verfahren zur Vorladung von Gleichspannungs-Zwischenkreisen von Wechselrichtern
CN109149549A (zh) * 2018-08-21 2019-01-04 上海交通大学 一种采用多电压均衡器并联的双极直流系统分层结构及控制方法
DE102019213067A1 (de) 2019-08-30 2021-03-04 Robert Bosch Gmbh Gleichspannungswandler und Verfahren zur Überprüfung eines Zwischenkreiskondensators an einem Gleichspannungswandler

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JP2023549105A (ja) 2023-11-22
US20230283069A1 (en) 2023-09-07
DE102020129917A1 (de) 2022-05-12
CN116438723A (zh) 2023-07-14

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