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
  • H02M1/32—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
  • H02M5/00—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases
  • H02M5/40—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc
  • H02M5/42—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters
  • H02M5/44—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac
  • H02M5/453—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal
  • H02M5/458—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
  • H02M5/4585—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only having a rectifier with controlled elements
• • 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
  • H02M7/003—Constructional details, e.g. physical layout, assembly, wiring or busbar connections
• • 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
  • 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

Definitions

• the invention relates to a device for converting an electrical current with at least one phase module, which has an AC voltage connection and at least one DC voltage connection, wherein a phase module branch is formed between each DC voltage connection and each AC voltage connection, and wherein each phase module branch is connected in series has submodules, each having at least one power semiconductor.
• Such a device is already known from DE 101 03 031 Al. There, both a classic voltage intermediate circuit converter and a voltage source converter with distributed energy storage devices are described. Voltage-source inverters with distributed or subdivided energy stores and the ability to switch staged voltages are also referred to as multilevel converters.
• the described voltage source converter is provided for connection to a polyphase AC voltage network, the converter being connected to a second converter via a DC voltage circuit.
• the second converter is connected on the AC side to another single-phase or multi-phase AC voltage network or to a load to be driven.
• the inverter has a phase module which has an AC terminal for connecting the phase of the AC mains and two DC terminals.
• phase module branches which are for achieving high voltages from a series circuit consist of turn-off power semiconductors.
• the turn-off power semiconductors are, for example, so-called IGBTs, GTOs or IGCTs.
• Each freewheeling diode which can be switched off is connected in parallel with a freewheeling diode.
• a central capacitor is provided as an energy store in the DC intermediate circuit.
• each phase module branch of the power converter thus consists of a series connection of submodules with their own energy stores.
• the object of the invention is therefore to provide a device of the type mentioned, which can withstand high short-circuit currents over a sufficient period of time.
• the invention solves this problem by semiconductor protection means in parallel and / or series connection to at least one of the power semiconductors.
• one or more components for protecting the power semiconductors are provided. These components are encompassed by the term semiconductor protection agent. Such a component is, for example, a unit in parallel with one of the power semiconductors.
• the semiconductor protection means also include current limiting means arranged to limit the flow of current through the phase module branches.
• the term power semiconductor encompasses here both the turn-off power semiconductors, ie IGBTs, GTOs, IGCTs or the like, as well as the freewheeling diodes, which are usually connected in parallel with the turn-off power semiconductors.
• each submodule has at least one turn-off power semiconductor, to which an opposite freewheeling diode is connected in parallel, wherein the semiconductor Protective means comprise a protective element which is connected in parallel to the opposite freewheeling diode.
• the protective element is a further freewheeling diode which has a current carrying capacity adapted to the expected short-circuit current.
• the actual freewheeling diode is connected in parallel with an additional freewheeling diode.
• the current flow in the event of a short circuit is therefore taken over by both freewheeling diodes.
• the static transmission characteristic of the freewheeling diode serving as a protective element is set up in relation to the already integrated free-wheeling diode so that in the event of a fault the protective element takes over a significant portion of the fault current and thus relieves the integrated freewheeling diode.
• Protective element acting freewheeling diode adapted to the expected loads.
• the current flowing across the respective phase module branch is split between the integrated freewheeling diode and the freewheeling diode acting as a protective element, the said division depending on the static forward characteristic of the two freewheeling diodes.
• both freewheeling diodes are also loaded, which is why the freewheeling diode acting as a protective element has requirements with regard to the specified loss of delay.
• the protective element is a thyristor. This is switched off in normal operation, so that a current flow through the thyristor is impossible.
• a short circuit can be detected by a voltage or current sensor in the DC voltage circuit, at the AC connection, or by measuring the branch current via the phase module branch. The way in which the short circuit is detected is within the scope of the invention. but anyway.
• one or more of said measuring sensors is connected to an evaluation unit, which determines the short-circuit case based on a logic implemented in it and subsequently generates a signal for igniting the thyristor or thyristors.
• the evaluation unit compares the measured current with a threshold current, for example, and determines the short-circuit case if the threshold current is exceeded for a prolonged period. Subsequently, the turn-off power semiconductors are transferred to their blocking position within a period in the order of magnitude of microseconds. The short-circuit current can then only flow through the parallel-connected freewheeling diodes. By a subsequent signal of the evaluation of the thyristor is transferred from its blocking position into its passage position in which a current flow is ü about the thyristor enabled. The short-circuit current therefore flows both via the thyristor and via the integrated freewheeling diode.
• a threshold current for example
• the static conduction characteristic of the thyristor is designed so that it takes over a significant portion of the fault short-circuit current, so that the integrated freewheeling diode is relieved.
• the periodic switching of the turn-off power semiconductors, which are parallel to the thyristor acting as a protective element, in normal operation must not lead to an undesired ignition of the thyristor.
• a self-ignition of the thyristor would be triggered, for example, by an excessive voltage gradient.
• the thyristor must therefore have a sufficient du / dt capability.
• the semiconductor protection means comprise inductors arranged in each phase module.
• the arrangement of the inductors within the phase module is basically arbitrary.
• each phase module is connected to one or each of the DC modules via the inductors. Voltage connections connected.
• the inductance is part of the phase module.
• the inductances are arranged between the series circuit of the submodules and the AC voltage connection.
• each Phasenm ⁇ dulzweig is connected by means of the inductors to the AC voltage terminal.
• the inductances of the phase module branches of the same phase module are thus arranged adjacent to one another, wherein the AC voltage connection is arranged between the inductors.
• the inductors can therefore also be inductively coupled to each other, whereby the total inductance for circulating currents between the phase modules and the DC component of the branch current is increased and the individual inductances are designed to reduce cost, if the
• Circular currents for the dimensioning can be decisive.
• the semiconductor protection means comprise inductors which are arranged in the submodules.
• each submodule has an inductance.
• the inductors are distributed according to this variant of the invention in the phase module.
• the semiconductor protection means comprise inductors which are arranged in the DC voltage circuit.
• the inductances are arranged in the immediate physical vicinity of the phase modules, so that a fault current generated by a
• the semiconductor protection means comprise inductors which are arranged on the AC side of the phase modules.
• the semiconductor protection means comprise transformer windings. The transformer windings are equipped with sufficient leakage inductance for effective current limitation.
• each submodule has a first connection terminal, a second connection terminal, an energy store and a power semiconductor branch having two series-connected turn-off power semiconductors connected in parallel to the energy store, each opposing freewheeling diode being connected in parallel and the connection point of the emitter of a first turn-off power semiconductor Power semiconductor branch and the anode, the first terminal and the connection point of the turn-off power semiconductor of the horaumleitzwei- ges and the freewheeling diode forming the second terminal the first turn-off power semiconductor associated opposing freewheeling diode.
• each submodule has a first connection terminal, a second connection terminal, an energy store and a power semiconductor branch having two series-connected turn-off power semiconductors connected in parallel to the energy store, each opposing freewheeling diode being connected in parallel and connecting the collector of a first turn-off power semiconductor Power semiconductor branch and the cathode, the opposite of the first turn-off power semiconductor freewheeling diode, the first terminal and the connection point of the shutdown Baren power semiconductor of the power semiconductor branch and the freewheeling diode form the second terminal.
• the invention also relates to a method for protecting power semiconductors of such a device, in which a short circuit on the DC side of the phase module is detected by measuring sensors, after detecting the short-circuit current, the turn-off power semiconductors are transferred to their disconnected position and then a thyristor is transferred as a semiconductor protection element in its forward position ,
• FIG. 1 shows a schematic illustration of an exemplary embodiment of the device according to the invention, illustrating the path of a fault current in the event of a short circuit;
• FIG. 2 shows a phase module of an embodiment of the device according to the invention with so-called
• Figure 3 shows a phase module of an embodiment of the device according to the invention with so-called multi-level topology
• FIG. 4 shows a replacement image representation of a submodule of the phase module according to FIG. 3.
• Figure 1 shows an embodiment of the device 1 according to the invention in a schematic representation.
• the device shown has three phase modules 2a, 2b and 2c, which are each connectable to a phase of the AC voltage network 7.
• each phase module 2 a, 2 b and 2 c has an AC voltage connection 3.
• each phase module 2 a, 2 b, 2 c has a positive DC voltage connection p and a negative DC voltage connection n, which is connected to the positive pole of a DC voltage intermediate circuit 5 or to the negative pole of the DC intermediate circuit 5.
• phase modules 2a, 2b, 2c each comprise two phase module branches, each of which extends between the AC voltage terminal 3 and one of the DC voltage connections p and n. Overall, six phase module branches are provided in the illustrated embodiment. Each phase module branch has a series connection of submodules with turn-off power semiconductors.
• the connection to the AC voltage network 7 shown as an ideal voltage source takes place, for example, via a transformer. Additional inductances can also be arranged between this transformer and the AC voltage connection 3.
• the stray inductances of the transformer, the additional inductances and the impedance of the AC voltage network 7 are illustrated in FIG. 1 by the inductances ⁇ a, 6b, 6c, which are arranged on the AC side of the phase modules 2a, 2b and 2c.
• a three-pole circuit breaker 8 is connected, which is connected to a protective device which is equipped with measuring sensors for detecting the AC voltage-side current flow of the phase modules. If the detected current exceeds a predetermined value Schwellenstror ⁇ , it comes to switching the circuit breaker 8, wherein each pole of the circuit breaker 8 is transferred to its disconnected position in which a current flow through the power switch 8 is interrupted.
• FIG. 1 also shows an exemplary path of one of the
• AC voltage 7 driven short-circuit current 10 illustrates that would occur in a DC circuit 5 in the case of a short circuit. It can be seen that the short-circuit current 10 from the AC voltage network 7 via the power switch 8, the inductance 6a, the power semiconductor of the phase module 2a, the inductors 9 in the positive and negative pole n of the DC voltage circuit 5, the power semiconductors of the phase module 2b Inductance 6b, and finally flows back into the AC voltage network 7.
• the inductors 9 arranged in the DC voltage circuit 5 thus limit the short-circuit current 10 and serve as semiconductor protection means within the scope of the invention.
• FIG. 2 shows a phase module 2a in two-point technology, again the path of a short-circuit current 10 is illustrated on the sensitive power semiconductor. It should be noted that all turn-off power semiconductors were transferred immediately after detecting the short shot by appropriate measurement sensors, which are connected to an evaluation unit, in their disconnected position. It can be seen in FIG. 2 that the phase module 2a is composed of two phase module branches 11p and Hn. In this case, the phase module branch Hp extends between the AC voltage terminal 3 and the positive DC voltage terminal p and the phase voltage The module module Hp, Hn again has a series connection of submodules, each submodule having a turn-off power semiconductor 12 and a freewheeling diode 13 connected in antiparallel to the turn-off power semiconductor.
• each phase module branch 11p or Hn The dotted line of each phase module branch is intended to indicate that the number of submodules and thus the turn-off power semiconductor 12 and the free-wheeling diodes 13 for each phase module branch 11p or Hn is not limited to two, but can be arbitrarily extended depending on the applied voltage.
• Short-circuit current described in connection with FIG. 1 would thus flow via the AC voltage terminal 3 of the phase module 2 a as well as via all freewheeling diodes 13 of the phase module branch H p to the positive pole of the DC voltage circuit 5.
• the free-wheeling diodes 13 of the phase module branch Hp or the freewheeling diodes of the phase module branch Hn of the phase module 2b would be exposed to the high short-circuit currents and could be damaged before the circuit breaker 8 trips.
• An inventive device which has a phase module according to FIG. 2, comprises a semiconductor protection means, preferably not shown in the form of a thyristor or a diode, connected in parallel to a power semiconductor, in particular a freewheeling diode, which loads the short-circuit current when the power semiconductors are switched off becomes.
• the device comprises a central energy storage, also not shown, for example in the form of a capacitor, which is connected to the converter of the device with low resistance.
• FIG. 3 shows a phase module 2 a of a so-called multi-level converter, which is likewise an exemplary embodiment of the device according to the invention.
• the phase module 2a comprises a series connection of submodules 15 which each have an energy store, so that graduated voltage profiles can be generated by connecting and disconnecting the submodules in the series connection. Due to the decentralized arrangement of the energy store in the phase module, it is possible to equip the phase module 2 a with an additional inductance 14, which is connected between the DC voltage connection p or n and the respective series circuit of bipolar submodules 15. The additional inductance limit the short-circuit current.
• An arrangement of the inductors in the phase modules is advantageous only in the multi-level technique. In converters with central energy storage, however, the inductances in the phase module have a negative effect on the switching behavior.
• FIG. 4 shows an equivalent circuit diagram of the submodule 15 according to FIG. 3. It can be seen that each submodule 15 has two turn-off power semiconductors 12, such as IGBTs. Again, each turn-off power semiconductor 12, a freewheeling diode 13 is connected in anti-parallel. In this way, a series circuit 16 is formed, which consists of the turn-off power semiconductors 12. The series circuit 16 is connected as a capacitor 17 formed energy storage in parallel.
• Each submodule 15 has a first connection terminal 18 and a second connection terminal 19. Between the terminals 18 and 19, a first power semiconductor 12a is arranged.
• the power semiconductor 12b is arranged in FIG. 4 above the turn-off power semiconductor 12a. After detecting a short circuit are first transferred the turn-off power semiconductors in their disconnected position. The short-circuit current therefore flows through the lower freewheeling diode 13a.
• the freewheeling diode 13b is not affected by the short-circuit current. For this reason, only the lower freewheeling diode 12 a, a protective element 20 is connected in parallel.
• the protective element 20 is a further freewheeling diode, wherein this has a transmission characteristic which, in relation to the integrated diode 13a, is such that, in the event of a fault, a substantial proportion of the short-circuit current flows via the freewheeling diode 20.
• the freewheeling diode 20 also has a sufficiently high surge current carrying capacity. During normal operation, the current flows both via the freewheeling diode 13a and via the freewheeling diode 20 acting as a protective element. The division depends on the static passage characteristics of the two freewheeling diodes 13a and 20. When commutating, therefore, the free-wheeling diode 20 is also loaded appropriate suitability in terms of shutdown must have. However, such freewheeling diodes are known to those skilled in the art, so that at this point a more detailed description of the diode properties can be omitted.
• Switch-off power semiconductors 12a with counter-rotating freewheeling diodes 13a which are arranged in a common housing, which is designated by 21 in FIG. 4, can be obtained on the market.
• the protective element, ie in this case the freewheeling diode 20, is arranged outside the housing 20.
• inductances 14 in the phase module 2 a, 2 b, 2 c or inductors 9 in the dc voltage circuit 5 may be present.
• the submodules 15 at least partially have an inductance.
• the branch current increases via the phase module 2 a at a speed which is essentially determined by the inductance 14. If the short circuit occurs on the DC side of the inductors 9 in the DC voltage circuit, these too limit the rate of current rise.
• the inductances 14 are designed, for example, such that, in the event of a short circuit, the turn-off power semiconductors can still be switched off within the permissible normal current range of the turn-off power semiconductors. For this reason, a fast detection and response is provided, which is on the order of a few microseconds. After switching off the disconnectable power semiconductors, only the freewheeling diodes will carry the short-circuit current. When using thyristors as protective element, they should be ignited after a few milliseconds.

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• 2006
  • 2006-12-08 JP JP2009539597A patent/JP5318774B2/ja active Active
  • 2006-12-08 PL PL06828680T patent/PL2100368T3/pl unknown
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  • 2006-12-08 ES ES06828680T patent/ES2369570T3/es active Active
  • 2006-12-08 DE DE200611004196 patent/DE112006004196A5/de not_active Withdrawn
  • 2006-12-08 AT AT06828680T patent/ATE523951T1/de active
  • 2006-12-08 CA CA2671819A patent/CA2671819C/en active Active
  • 2006-12-08 CN CN2006800565621A patent/CN101548461B/zh active Active
  • 2006-12-08 DK DK06828680T patent/DK2100368T3/da active
  • 2006-12-08 EP EP20060828680 patent/EP2100368B1/de active Active
  • 2006-12-08 US US12/517,641 patent/US8817440B2/en active Active
  • 2006-12-08 WO PCT/DE2006/002249 patent/WO2008067786A1/de active Application Filing

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