Electrical arrangement comprising sub-modules

An arrangement includes at least one series circuit having at least two series-connected submodules and an inductor. At least one of the submodules in one or a plurality of the series circuits has a step-up/step-down converter and a storage module. A protective module with at least one actuator is electrically connected between the step-up/step-down converter and the storage module. A method for operating the arrangement is also provided.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to an arrangement which comprises at least one series circuit including at least two series-connected submodules and an inductor.

A corresponding arrangement is described in international patent application WO 2012/156261 A2. This arrangement relates to a multi-level converter.

SUMMARY OF THE INVENTION

The object of the present invention is to improve an arrangement of the kind initially specified with respect to operational reliability.

This object is achieved according to the present invention via an arrangement having at least one series circuit including at least two series-connected submodules and an inductor. Advantageous embodiments of the arrangement according to the present invention are provided in the sub claims.

Accordingly, it is provided according to the present invention that at least one of the submodules of one or a plurality of the series circuits includes a step-up/step-down converter and a storage module, and a protective module including at least one actuator is electrically connected between the step-up/step-down converter and the storage module.

A significant advantage of the arrangement according to the present invention may be seen in the fact that, in the case of a fault, the storage module may be disconnected from the step-up/step-down converter with the aid of the actuator, and it may thus be prevented that the energy stored in the storage module is able to feed a fault location in the step-up/step-down converter or in a module of the arrangement which is upstream of the step-up/step-down converter, and is able to result in additional damage or total destruction of the arrangement. In other words, the protective module is able to protect the arrangement from internal destruction via the energy in the storage module, after a fault has been detected and, for example, a disconnection of the arrangement from an external power distribution network has just taken place, and feeding the fault location externally via the power distribution network has just been prevented. The protective module thus prevents an internal feed of the fault location and is able to assist safety devices which are provided for disconnecting the arrangement from an external power distribution network and for preventing an external feed of the fault location.

The arrangement is preferably a converter arrangement, in particular a converter arrangement in the form of a multi-level converter.

Preferably, the actuator or one of the actuators of the protective module is an electrical switch which is electrically arranged in such a way that, in the activated state, it short-circuits a first and a second input terminal via which the protective module is connected to the step-up/step-down converter, and/or it short-circuits a first and a second output terminal via which the protective module is connected to the storage module.

According to a preferred embodiment variant of the arrangement, it is provided that the protective module has a first and a second input terminal for connecting to the step-up/step-down converter, and at least two actuators, of which one actuator is connected between the first input terminal of the protective module and an internal terminal of the protective module, and one actuator is connected between the internal terminal of the protective module and the second input terminal.

According to an additional preferred embodiment variant of the arrangement, it is provided that the protective module has a first and a second output terminal for connecting to the storage module, and at least two actuators, of which one actuator is connected between the first output terminal of the protective module and an internal terminal of the protective module, and one actuator is connected between the internal terminal of the protective module and the second output terminal.

It is considered to be particularly advantageous if the protective module has a first and a second input terminal for connecting to the step-up/step-down converter, and has a first and a second output terminal for connecting to the storage module, and the second input terminal and the second output terminal are connected.

Preferably, the protective module has at least three actuators, of which a first actuator is connected between an internal terminal of the protective module and the second input terminal of the protective module, a second actuator is connected between the first output terminal of the protective module and the internal terminal of the protective module, and a third actuator is connected between the first input terminal of the protective module and the internal terminal of the protective module.

The first actuator is preferably a switch. With a view to short switching times and reliable activation or reliable closing, it is considered to be advantageous if the first actuator is an irreversibly switching switch, in particular a pyrotechnically driven switch.

The second and/or third actuator preferably has a fuse or is formed by such a fuse.

With a view to particularly reliable protection of the arrangement, it is considered to be advantageous if the protective module has a triggering unit which generates a trigger signal for activating or electrically closing at least one of the actuators, in particular the first actuator, if at least one electrical value, in particular a measured value, indicates a fault, in particular reaches or exceeds a predefined threshold.

Preferably, the triggering unit is designed in such a way that it generates the trigger signal if the magnitude of the current at the first or second input terminal of the protective module reaches or exceeds a predefined first current threshold, the magnitude of the current at the first or second output terminal of the protective module reaches or exceeds a predefined second current threshold, and/or the magnitude of the voltage between the first and second output terminals of the protective module reaches or exceeds a predefined voltage threshold.

It is also advantageous if the triggering unit is designed in such a way that it activates at least one switch in the upstream step-up/step-down converter if the magnitude of the current at the first or second input terminal of the protective module reaches or exceeds the first current threshold.

In addition, the present invention relates to a method for operating an arrangement which comprises at least one series circuit including at least two series-connected submodules and an inductor.

With respect to such a method, it is provided according to the present invention that at least one of the submodules of one or a plurality of the series circuits comprises a step-up/step-down converter and a storage module, and a protective module including at least one actuator is electrically connected between the step-up/step-down converter and the storage module, and the protective module disconnects the step-up/step-down converter from the storage module if at least one electrical value indicates a fault.

With respect to the advantages of the method according to the present invention, reference is made to the above embodiments in conjunction with the arrangement according to the present invention.

DESCRIPTION OF THE INVENTION

For the sake of clarity, in the figures, the same reference characters are always used for identical or comparable components.

FIG. 1shows an arrangement10which comprises a converter device20, a control circuit30, a current sensor40, and a voltage sensor50.

The converter device20has three alternating-current input terminals E20a, E20b, and E20c, which are connected to a three-phase electrical line80. Via the three-phase line80, the converter device20is connected to a terminal busbar90and a power distribution network100which is only schematically indicated.

The arrangement10according toFIG. 1may, for example, be operated as follows:

By means of the current sensor40, the control circuit30measures the three-phase input alternating current Ie flowing on the input side into the converter device20(or flowing out of it), and, via the voltage sensor50, measures the three-phase input voltage which is present at the converter device20, and determines the state of the power distribution network100via the measured values. In addition, said control circuit ascertains the operating state of the converter device20based on measured values which are detected inside the converter device20by current and/or voltage sensors which are not shown further.

With the aid of the measured values, the control circuit30ascertains an optimal control of the converter device20in such a way that the power distribution network100assumes a most optimal network state, and the converter device20is in an advantageous operating state in which power may be provided or consumed at any time.

FIG. 2shows an exemplary embodiment of a converter device20which may be used in the arrangement10according toFIG. 1. The three alternating-current voltage input terminals E20a, E20b, and E20care shown, which are connected to the three-phase line80according toFIG. 1. The three phases of the three-phase line80are indicated inFIG. 2by the reference characters L1, L2, and L3.

The converter device20has three delta-connected series circuits200, the series-connected components of which are not depicted in greater detail inFIG. 2for reasons of clarity.

FIG. 3shows an exemplary embodiment of a series circuit200which may be used in the converter device20according toFIG. 2. The series circuit200according toFIG. 3has a current sensor210which is preferably connected to the control circuit30according toFIG. 1, a plurality of submodules220, and an inductor230. The current sensor210, the submodules220, and the inductor230are electrically connected in series. The series connection of the submodules220takes place via the input terminals E220aand E220b.

FIG. 4shows an exemplary embodiment of a submodule220which may be used in the series circuit200according toFIG. 3. The submodule220comprises an input module221which is a converter module for AC/DC (alternating current/direct current) conversion, a step-up/step-down converter222, a storage module223, and a protective module225which is connected between the step-up/step-down converter222and the storage module223.

The input module221, the step-up/step-down converter222, the protective module225, and the storage module223are cascaded in succession. This means that the outputs A221aand A221bof the input module221are connected to the inputs E222aand E222bof the step-up/step-down converter222, and the outputs A222aand A222bof the step-up/step-down converter222are connected to the inputs E225aand E225bof the protective module225, and the outputs A225aand A225bof the protective module225are connected to the inputs E223aand E223bof the storage module223. The inputs E221aand E221bof the input module221according toFIG. 4form the inputs E220aand E220bof the submodule220, which are connected in series to the inputs E221aand E221bof input modules221of upstream and downstream submodules220(cf.FIG. 3) for forming the series connection of the submodules220(cf.FIG. 3).

As an energy store, the storage module223preferably has one or multiple double-layer capacitors which are not depicted in greater detail inFIG. 4for reasons of clarity.

FIG. 5shows an exemplary embodiment of an input module221which may be used in the submodule220according toFIG. 4. The input module221comprises two switching elements S1and S2, to which a diode is connected in parallel in each case. The switching elements S1and S2may, for example, be semiconductor switches, for example, in the form of transistors. The outputs of the input module221are indicated inFIGS. 4 and 5by the reference characters A221aand A221band are connected to the inputs E222aand E222bof the downstream step-up/step-down converter222.

The control of the switching elements S1and S2of the input module221preferably takes place via the control circuit30according toFIG. 1, as a function of the current and voltage values which the control circuit30detects and evaluates.

FIG. 6shows an additional exemplary embodiment of an input module221which may be used in the submodule220according toFIG. 4. The input module221comprises four switching elements S1, S2, S3, and S4, to which a diode is connected in parallel in each case. The four switching elements S1to S4are interconnected in the form of a H bridge circuit and are preferably controlled by the control circuit30according toFIG. 1, as a function of the current and voltage values which are supplied by the two sensors40and50and the remaining sensors already mentioned but not shown in greater detail. The outputs of the input module221are indicated inFIGS. 4 to 6by the reference characters A221aand A221band are connected to the inputs E222aand E222bof the downstream step-up/step-down converter222.

FIG. 7shows an exemplary embodiment of a step-up/step-down converter222which may be used in the submodule220according toFIG. 4. The step-up/step-down converter222according toFIG. 7has four switching elements S5, S6, S7, and S8, to which a diode is connected in parallel in each case. The four switching elements S5, S6, S7, and S8are connected in the form of an H bridge circuit H222, the outer terminals of which form the inputs E222aand E222bof the step-up/step-down converter222.

A capacitor C is connected in parallel with the H bridge circuit H222and is thus also in parallel with the input terminals E222aand E222bof the step-up/step-down converter222.

Center terminals M1and M2of the H bridge circuit H222are connected to the output terminals A222aand A222bof the step-up/step-down converter222via an inductor L in each case, preferably in the form of a choke. Alternatively, in addition, only one of the two center terminals M1or M2of the H bridge circuit H222may be connected to the respective output terminal A222aor A222bof the step-up/step-down converter222via an inductor L, preferably in the form of a choke.

The output terminals A222aand A222bof the step-up/step-down converter222are connected to the input terminals E225aand E225bof the downstream protective module225(cf.FIG. 4).

The control of the four switching elements S5, S6, S7, and S8preferably takes place via the control circuit30according toFIG. 1, as a function of the measured values which are supplied by the two sensors40and50and the remaining sensors already mentioned but not shown in greater detail.

FIG. 8shows an additional exemplary embodiment of a step-up/step-down converter222which may be used in the submodule220according toFIG. 4. The step-up/step-down converter222according toFIG. 8has two switching elements S5and S6, to which a diode is connected in parallel in each case. The two switching elements S5and S6are connected in series.

A capacitor C is connected in parallel with the series circuit of the switching elements S5and S6and is thus also in parallel with the input terminals E222aand E222bof the step-up/step-down converter222.

A center terminal M1of the series circuit is connected to the output terminal A222aof the step-up/step-down converter222via an inductor L, preferably in the form of a choke.

The output terminals A222aand A222bof the step-up/step-down converter222are connected to the input terminals E225aand E225bof the downstream protective module225(cf.FIG. 4).

The control of the two switching elements S5and S6takes place preferably via the control circuit30according toFIG. 1, as a function of the measured values which are supplied by the two sensors40and50and the remaining sensors already mentioned but not shown in great detail.

FIG. 9shows an exemplary embodiment of a protective module225which may be used in the submodule220according toFIG. 4.

The protective module225has three actuators A1, A2, and A3, of which a first actuator A1is connected between an internal terminal Q225of the protective module225and the lower input terminal E225bof the protective module225inFIG. 9, a second actuator A2is connected between the upper output terminal A225aof the protective modules225inFIG. 9and the internal terminal Q225of the protective module225, and a third actuator A3is connected between the upper input terminal E225aof the protective module225inFIG. 9and the internal terminal Q225of the protective module225.

The first actuator A1is a switch, preferably an irreversibly switching switch, in particular a pyrotechnically driven switch.

The second and third actuators A2and A3are preferably fuses.

In addition, the protective module225has a current sensor500for measuring the current I225eat the input terminal E225aof the protective module225, a current sensor510for measuring the current I225aat the output terminal A225aof the protective module225, and a voltage sensor530for measuring the voltage U225between the output terminals A225aand A225bof the protective module225.

In addition, the protective module225is equipped with a triggering unit540which generates a trigger signal ST1for activating or electrically closing the first actuator A1if at least one of the measured values of the current sensor500, the current sensor510, or the voltage sensor530indicates a fault, in particular reaches or exceeds a predefined threshold.

The triggering unit540is preferably designed in such a way that it generates the trigger signal ST1if the magnitude of the current I225ereaches or exceeds a predefined first current threshold, the magnitude of the current I225areaches or exceeds a predefined second current threshold, and/or the magnitude of the voltage U225between the first and second output terminals of the protective module225reaches or exceeds a predefined voltage threshold.

In the exemplary embodiment according toFIG. 9, the triggering unit540is preferably also designed in such a way that it generates a trigger signal ST2if the magnitude of the current I225ereaches or exceeds the predefined first current threshold. The triggering unit540transmits the trigger signal ST2to the upstream step-up/step-down converter222and thus activates its switching element S6in the case of the step-up/step-down converter222according toFIG. 8, or its switching elements S6and S8in the case of the step-up/step-down converter222according toFIG. 7.

FIG. 10shows an exemplary embodiment of a triggering unit540according toFIG. 9in greater detail. Three absolute-value generators550,551, and552are shown, on the input side of which measured values Mw1, Mw2, and Mw3are present. The measured value Mw1is generated by the current sensor500(cf.FIG. 9) and indicates the magnitude of the current I225e; the measured value Mw2is generated by the current sensor510and indicates the magnitude of the current I225a; and the measured value Mw3is generated by the voltage sensor530and indicates the magnitude of the voltage U225.

The three absolute-value generators550,551and552form the magnitudes from the measured values Mw1to Mw3and pass them to the downstream comparators560,561, and562. The comparators560,561, and562generate a logical “one” on the output side in each case, if the magnitude present on the input side reaches or exceeds a predefined threshold; otherwise, a logical “zero” is generated. The output signal of the comparator560directly forms the aforementioned trigger signal ST2for activating or electrically closing switching elements of the upstream step-up/step-down converter222.

Downstream of the comparators560,561, and562is an OR gate570, at which the logical output signals of the comparators560,561, and562are present on the input side. The OR gate570generates a logical “one” and thus the trigger signal ST1for activating or electrically closing the first actuator A1, if at least one logical “one” is present on the input side, i.e., if at least one of the measured values of the current sensor500, the current sensor510, or the voltage sensor530indicates a fault, in particular reaches or exceeds a predefined threshold.

FIG. 11shows an additional exemplary embodiment of a converter device20which may be used in the arrangement10according toFIG. 1. Unlike the exemplary embodiment according toFIG. 2, the series circuits200of the converter device20are not interconnected in a delta configuration, but rather in a star configuration, thus forming a star connection. The neutral point formed by the interconnection is indicated inFIG. 11by the reference characters ST. A return line N, for example, the return line of the three-phase line80according toFIG. 1, may be connected to the neutral point ST.

The configuration of the series circuits200is not depicted in greater detail inFIG. 11for reasons of clarity. The series circuits200may, for example, correspond to the series circuits200of the converter device20according toFIG. 2, or may be configured in such a way as has been described above in detail by way of example in conjunction withFIGS. 3 to 8. With respect to the configuration of the series circuits200according toFIG. 11, the above embodiments apply accordingly.

FIG. 12shows an exemplary embodiment of a converter device20in which series circuits200, which respectively include at least two series-connected submodules which are not shown for reasons of clarity inFIG. 12, form a bridge circuit400.

The configuration of the series circuits200of the converter device20may, for example, correspond to the configuration of the series circuits200, as has been described above in detail in conjunction withFIGS. 2 to 8.

FIG. 13shows an exemplary embodiment of a single-phase converter device20which comprises a series circuit200including a plurality of series-connected submodules which are not depicted in greater detail inFIG. 13for reasons of clarity. The configuration of the series circuit200of the arrangement20according toFIG. 13may correspond to the series circuits200as have been described above in detail in conjunction withFIGS. 2 to 8.

The converter device20or the series circuit200may be connected to a single-phase AC voltage network (as shown) or alternatively to a DC voltage network, for example, to a DC voltage circuit of a high-voltage direct-current (HVDC) transmission facility. In the latter case, the input module221is preferably a DC/DC converter or a DC voltage/DC voltage converter.

Although the present invention has been illustrated and described in greater detail via preferred exemplary embodiments, the present invention is not limited by the disclosed examples, and other variations may be derived from it by those skilled in the art, without departing from the protective scope of the present invention.

LIST OF REFERENCE CHARACTERS

10Arrangement20Converter device30Control circuit40Current sensor50Voltage sensor80Electrical line90Terminal busbar100Power distribution network110Direct-current electrical line200Series circuit210Current sensor220Submodules221Input module222Step-up/step-down converter223Storage module225Protective module230Inductor400Bridge circuit500Current sensor510Current sensor530Voltage sensor540Triggering unit550Absolute-value generator551Absolute-value generator552Absolute-value generator560Comparator561Comparator562Comparator570OR gateA1ActuatorA2ActuatorA3ActuatorA221aOutput terminal of the input moduleA221bOutput terminal of the input moduleA222aOutput terminal of the step-up/step-down converterA222bOutput terminal of the step-up/step-down converterA225aOutput terminal of the protective moduleA225bOutput terminal of the protective moduleC CapacitorE20aAC voltage input terminalE20bAC voltage input terminalE20cAC voltage input terminalE220aInput terminal of the submoduleE220bInput terminal of the submoduleE221aInput terminal of the input moduleE221bInput terminal of the input moduleE222aInput terminal of the step-up/step-down converterE222bInput terminal of the step-up/step-down converterE223aInput terminal of the storage moduleE223bInput terminal of the storage moduleH222H bridge circuitE225aInput terminal of the protective moduleE225bInput terminal of the protective moduleI225eCurrentI225aCurrentIe Input alternating currentL InductorL1PhaseL2PhaseL3PhaseM1Center terminalM2Center terminalMw1Measured valueMw2Measured valueMw3Measured valueN Return lineQ225Internal terminal of the protective moduleST Neutral pointST1Trigger signalST2Trigger signalS1Switching elementS2Switching elementS3Switching elementS4Switching elementS5Switching elementS6Switching elementS7Switching elementS8Switching elementU225Voltage