Multi-phase converter topology for multi-phase and single-phase operation

Description

[0001] A multi-phase converter topology serves to convert alternating voltages supplied by a power grid at an AC input into a direct voltage present at a DC output. The multi-phase converter topology should be able to operate from both a multi-phase and a single-phase power grid. The number of available grid phases of the power grid is determined by... m, m > 1, denotes (usually lies m = 3 before).

[0002] In principle, both multiphase and single-phase operation can be achieved with a conventional multiphase converter topology, i.e., operation in conjunction with a multiphase or single-phase supply network on the AC side. A conventional multiphase converter topology is in Fig. 1 schematically represented and has a mains voltage input 15 (having mmains phase connections 18 and an earth connection 19), a DC voltage output 16 (having a positive and a negative terminal) and the following basic components: A Mains filter 12 showing m Network phase connections, an earthing connection, m Switching voltage terminals and a midpoint voltage terminal. The mains filter has w mains filter stages 121, 122, 123, where the variable ' w ' can take on integer values ​​greater than or equal to one. Each network filter stage has m + 1 input ports, m + 1 output terminal and one ground terminal. For 1 ≤ k ≤ m The following applies: ∘ The k -th output terminal of the first mains filter stage 121 forms the k- ten switching voltage connection of the mains filter 12. ∘ The k -th input port of the w -th mains filter stage forms the k -th mains phase connection of the mains filter 12 and thus thek- ten mains phase connection of the mains voltage input 14 of the multi-phase converter topology. The ( m The +1)th output terminal of the first mains filter stage 121 forms the midpoint voltage terminal of the mains filter. w > 1 applies for 1 ≤ k ≤ m+ 1 and 1 ≤ u < w that the k -th input port of the u -th mains filter stage with the k -th output port of the ( u +1)-th mains filter stage is connected. The grounding terminals of all mains filter stages are connected to each other and form the grounding terminal of the mains filter, which is connected to the grounding terminal of the mains voltage input of the multi-phase converter topology. A Power section 11 having a positive terminal, a negative terminal, a midpoint voltage terminal, m Switching voltage connections and m Half-bridges111, 112, 113 each having a positive terminal, a negative terminal, a midpoint voltage terminal, and a switching voltage terminal. The positive terminals of all m Half-bridges are connected to each other and form the positive terminal of the power section. The midpoint voltage terminals of all m Half-bridges are connected to each other and form the midpoint voltage connection of the power section. The negative terminals of all m Half-bridges are connected to each other and form the negative terminal of the power section. For 1 ≤ k ≤ m The following applies: the switched voltage connection of the k -th half-bridge forms the k -th switching voltage connection of the power section. One or more DC power supplies13; 131, 132, 133 each having a grounding terminal, an input terminal block having a positive terminal, a midpoint voltage terminal and a negative terminal, and an output terminal block having a positive terminal, a midpoint voltage terminal and a negative terminal. The number of DC voltage blocks is indicated by g designated and g can take on integer values ​​greater than or equal to one. Depending on the design of the DC block, the midpoint voltage connection of the input terminal block of the DC block, the midpoint voltage connection of the output terminal block of the DC block, or the midpoint voltage connections of the input and output terminal blocks may be omitted. The ground connections of all DC blocks are connected to the ground connection of the mains voltage input of the multiphase converter topology. gIf > 1 applies, then the DC voltage blocks are connected to each other as follows, where 1 ≤ f < g The following applies: ∘ The positive terminal of the output terminal block of the f -th DC voltage block is connected to the positive terminal of the input terminal block of the ( f +1)-th DC voltage block connected. ∘ The midpoint voltage terminal of the output terminal block of the f- The ten DC voltage blocks are connected to the midpoint voltage terminal of the input terminal block of the ( f +1)-th DC voltage block connected. ∘ The negative terminal of the output terminal block of the f -th DC voltage block is connected to the negative terminal of the input terminal block of the ( f +1)-th DC voltage block connected. DC / DC converter block 14 comprising an input terminal block, comprising a positive terminal, a midpoint voltage terminal and a negative terminal, and an output terminal block, comprising a positive terminal and a negative terminal.

[0003] For 1 ≤ k ≤ m applies: the k The -te switching voltage connection of the power section is connected to the k- The positive terminal of the power supply is connected to the positive terminal of the input terminal block of the first DC voltage block. The negative terminal of the power supply is connected to the negative terminal of the input terminal block of the first DC voltage block. The midpoint voltage terminal of the power supply is connected to the midpoint voltage terminal of the mains filter and the midpoint voltage terminal of the input terminal block of the first DC voltage block.

[0004] The positive terminal of the output terminal block of the g The -ten DC voltage block is connected to the positive terminal of the input terminal block of the DC voltage converter block 14. The midpoint voltage terminal of the output terminal block of the gThe -ten DC voltage block is connected to the midpoint voltage terminal of the input terminal block of the DC-DC converter block. The negative terminal of the output terminal block of the g The negative terminal of the DC-DC block is connected to the negative terminal of the input terminal block of the DC-DC converter block. The positive terminal of the output terminal block of the DC-DC converter block forms the positive terminal of the DC-DC output of the conventional multi-phase converter topology. The negative terminal of the output terminal block of the DC-DC converter block forms the negative terminal of the DC-DC output 16 of the conventional multi-phase converter topology.

[0005] For single-phase operation of the conventional multi-phase converter topology, two basic operating modes are known: 1. A first phase of the conventional multi-phase converter topology is used as the forward conductor, a second phase of the conventional multi-phase converter topology is used as the return conductor, and the remaining phases of the conventional multi-phase converter topology are not used. This operating mode is suitable for m = 3 and for operation with the line-to-line voltage, as occurs, for example, in a three-phase network during a phase failure, as described in M. Hartmann, «Ultra-Compact and Ultra-Efficient Three-Phase PWM Rectifier Systems for More Electric Aircraft», PhD Dissertation ETH No. 19755, ETH Zurich, 2011. Provided that the maximum permissible RMS current per phase is the same in three-phase and single-phase operation, this leads to a reduction in the rated power of the conventional multi-phase converter topology to approximately 58% of the rated power in three-phase operation during single-phase operation. If this operating mode is used form = 3. If only the phase voltage (approx. 58% of the line-to-line voltage) is used, the rated power of the conventional multi-phase converter topology can be reduced to approximately 33% of the rated power in three-phase operation. 2. One or more phases of the conventional multi-phase converter topology are used as the supply conductor, one or more phases of the conventional multi-phase converter topology are used as the return conductor, and the remaining phases of the conventional multi-phase converter topology are not used. This operating mode may allow for an increase in the rated power, but is particularly problematic in the practically important case of m = 3 is of minor importance, as saturation of the common-mode filter chokes present in the AC filter may occur.

[0006] EP 3242382 describes a converter system for converting a three-phase or single-phase AC voltage into a DC voltage, wherein the converter system comprises three converter branches, each converter branch having a first input and a second input to be supplied with a single-phase AC voltage and a first output and a second output providing a DC voltage. The converter system is designed to connect the first input of each converter branch to a phase of a three-phase network and the first inputs of the converter branches to a phase of a single-phase network, and to connect the interconnected second inputs of the converter branches to a neutral point of the three-phase network or the single-phase network.

[0007] CN 107 947 309 A discloses a three-phase converter that implements three-phase and single-phase operation, comprising a switch block, a choke group consisting of three chokes, a three-phase rectifier module, and a DC transformation module connected in series. In single-phase operation, the single-phase current-carrying line is connected to the three-phase rectifier module via two reactances each, and the single-phase neutral conductor is directly connected to the three-phase rectifier module.

[0008] Task The present invention therefore aims to realize a circuit that can be operated on both multi-phase and single-phase networks and allows for improved single-phase operation compared to known multi-phase topologies. A further possible objective is to achieve at least approximately the same rated power for single-phase and multi-phase operation.

[0009] The problem is at least partially solved by the inverter topology according to the patent claims.

[0010] The multi-phase converter topology for transferring electrical energy from an AC voltage input with m mains phase connections to a DC voltage output or vice versa, features: a power section with half-bridges for switching currents, an AC voltage filter connected between the power section and the AC voltage input, comprising at least one AC voltage filter stage with m + 1 input ports, m + 1 output terminals and one ground terminal; one or more DC voltage filters connected between the power section and the DC output;

[0011] The m mains phase connections are connected in parallel to each other and form a first phase connection for the connection of a single-phase AC voltage, and a neutral conductor connection of the AC voltage filter forms a neutral conductor connection of the AC voltage input and a second phase connection for the connection of the single-phase AC voltage.

[0012] This makes it possible to connect all phase connections in parallel in single-phase operation, whereby the phase currents of the m individual phases flow through the first m windings, and a return current - corresponding to the sum of the phase currents - flows through the ( m +1)-th winding. This allows the same rated power to be transmitted in single-phase operation as in multi-phase operation.

[0013] In embodiments, the AC voltage filter has at least one (m+1)-phase common-mode filter choke which does not saturate during single-phase operation of the universal multi-phase converter.

[0014] The common-mode filter choke is therefore dimensioned in such a way that currents occurring during single-phase operation lead to magnetic fluxes which cancel each other out on average over time.

[0015] In various embodiments, the AC voltage filter has at least one ( m +1)-phase common-mode filter choke, wherein all m+1 windings of the at least one (m +1)-phase common-mode filter choke have the same number of turns and the same winding direction.

[0016] In embodiments, the first m The windings have the same first conductor cross-section, and one in the ( m The wire in the +1)-th winding has a conductor cross-section which m-times the cross-sectional area of ​​the first conductor.

[0017] According to the invention, the multi-phase converter topology comprises a DC-DC converter block with two DC-DC converters, the The inputs are switchable between a series and a parallel arrangement, and their outputs, connected in parallel, form the DC voltage output, the power section having half-bridges which include a converter with three form voltage levels; and a control system designed to operate the converter topology either in multiphase operation with three voltage levels or in single-phase operation with two voltage levels.

[0018] The power section features half-bridges for switching three voltage levels. The outputs of a DC voltage block form the DC voltage output.

[0019] The invention will now be explained in more detail with reference to preferred embodiments, which are illustrated in the accompanying drawings. These schematically depict: Figure 1 shows a converter topology according to the prior art; Figure 2 shows a converter topology according to the invention; Figures 3-6 show embodiments of half-bridges; Figures 7-9 show embodiments of AC voltage filter stages; Figures 10-15 show embodiments of DC voltage filter blocks; Figure 16 shows an embodiment of a DC voltage converter; Figures 17-20 show embodiments of common-mode filter chokes; and Figures 21-23 show variants of converter topologies.

[0020] Fig. 2 schematically shows a universal multi-phase converter topology, having an AC voltage input 25 (having mMains phase connections 28, a neutral conductor connection 27 and an earth connection 29), a DC voltage output 26 (having a positive and a negative connection) and the following basic components: A AC voltage filter showing 22 m Network phase connections, a neutral conductor connection, an earthing connection, m Switching voltage terminals and a midpoint voltage terminal. The AC voltage filter 22 has w AC voltage filter stages 221, 222, 223, where the variable ` w ` can take on integer values ​​greater than or equal to one. Each AC voltage filter stage 221, 222, 223 has m + 1 input ports, m + 1 output terminal and one ground terminal. For 1 ≤ k ≤ m The following applies: ∘ The k -th output terminal of the first AC filter stage 221 forms the k -th switching voltage connection of the AC voltage filter. ∘ The k-th input port of the w The -th AC filter stage forms the k -th mains phase connection of the AC filter and thus the k -th mains phase connection of the mains voltage input of the multi-phase converter topology. The ( m The +1)th output terminal of the first AC filter stage 221 forms the midpoint voltage terminal of the AC filter. The ( m+ 1)th input port of the w The -ten AC voltage filter stage forms the neutral conductor connection of the AC voltage filter and thus the neutral conductor connection of the mains voltage input of the multi-phase converter topology. At w > 1 applies for 1 ≤ k ≤ m+ 1 and 1 ≤ u < w that the k -th input port of the u -th AC filter stage with the k -th output port of the ( u+1)-th AC filter stage is connected. The grounding terminals of all AC filter stages are connected to each other and form the grounding terminal of the AC filter, which is connected to the grounding terminal of the mains voltage input of the multiphase converter topology. A Power section 21. One or more DC power supplies 23. One DC / DC converter block 24.

[0021] The structure of the connections between the blocks can be the same as in the Figure 1 unless another embodiment described below exists.

[0022] For 1 ≤ k ≤ m applies: the k The -te switching voltage connection of the power section 21 is connected to the kThe positive terminal of the power section 21 is connected to the positive terminal of the input terminal block of the first DC voltage block 231. The negative terminal of the power section 21 is connected to the negative terminal of the input terminal block of the first DC voltage block 231. The midpoint voltage terminal of the power section 21 is connected to the midpoint voltage terminal of the AC voltage filter and to the midpoint voltage terminal of the input terminal block of the first DC voltage block 231.

[0023] Implementation of the universal multiphase converter topology with DC-DC converter block: The following connections apply here: Positive terminal of the output terminal block of the g-th DC voltage block 233 with the positive terminal of the input terminal block of the DC voltage converter block 24, midpoint voltage terminal of the output terminal block of the g-th DC voltage block 233 with the midpoint voltage terminal of the input terminal block of the DC voltage converter block 24, negative terminal of the output terminal block of the g-th DC voltage block 233 with the negative terminal of the input terminal block of the DC voltage converter block 24.

[0024] The positive terminal of the output terminal block of the DC-DC converter block 24 forms the positive terminal of the DC-DC output 26 of the universal multi-phase converter topology. The negative terminal of the output terminal block of the DC-DC converter block 24 forms the negative terminal of the DC-DC output 26 of the universal multi-phase converter topology. Examples of half-bridge designs:

[0025] One embodiment of the half-bridge with two voltage levels ( Fig. 3 )The circuit comprises two power switches 31, each comprising a switching element 32 and an antiparallel diode 33 connected in parallel (if, for example, a MOSFET is used as the power switch, the antiparallel diode is already present due to the internal semiconductor structure of the MOSFET). The two power switches of the two-voltage-level half-bridge are connected in series such that the anode of the antiparallel diode of the first power switch of the two-voltage-level half-bridge is connected to the cathode of the antiparallel diode of the second power switch of the two-voltage-level half-bridge. The two-voltage-level half-bridge has three terminals: a switching voltage terminal, a positive terminal, and a negative terminal.The switching voltage terminal of the two-level half-bridge is connected to the anode of the antiparallel diode of the first power switch of the two-level half-bridge, the positive terminal of the two-level half-bridge is connected to the cathode of the antiparallel diode of the first power switch of the two-level half-bridge, and the negative terminal of the two-level half-bridge is connected to the anode of the antiparallel diode of the second power switch of the two-level half-bridge. The midpoint voltage terminal is not used in this embodiment of the two-level half-bridge. This embodiment is not according to the invention.

[0026] One embodiment of an FCM (Flying Capacitor Multilevel) half-bridge ( Fig. 4 ) It has four circuit breakers 41 and one capacitor 42. The four circuit breakers of each FCM half-bridge are connected as follows: The anode of the antiparallel diode of the first power switch of the FCM half-bridge is connected to the cathode of the antiparallel diode of the second power switch of the FCM half-bridge, the anode of the antiparallel diode of the second power switch of the FCM half-bridge is connected to the cathode of the antiparallel diode of the third power switch of the FCM half-bridge, the anode of the antiparallel diode of the third power switch of the FCM half-bridge is connected to the cathode of the antiparallel diode of the fourth power switch of the FCM half-bridge.

[0027] The capacitor of the FCM half-bridge has two terminals. The first terminal of the capacitor is connected to the anode of the first power switch of the FCM half-bridge. The second terminal of the capacitor is connected to the cathode of the fourth power switch of the FCM half-bridge. The FCM half-bridge has three terminals: a switching voltage terminal, a positive terminal, and a negative terminal. The switching voltage terminal is connected to the anode of the antiparallel diode of the second power switch. The positive terminal is connected to the cathode of the antiparallel diode of the first power switch. The negative terminal is connected to the anode of the antiparallel diode of the fourth power switch.The midpoint voltage connection is not used in the embodiment of the FCM half-bridge.

[0028] An embodiment of an active T-type half-bridge ( Fig. 5 ) has four circuit breakers 51, which are connected as follows: The anode of the antiparallel diode of the first power switch of the active T-type half-bridge is connected to the cathode of the antiparallel diode of the second power switch of the active T-type half-bridge, the anode of the antiparallel diode of the second power switch of the active T-type half-bridge is connected to the anode of the antiparallel diode of the third power switch of the active T-type half-bridge, the anode of the antiparallel diode of the first power switch of the active T-type half-bridge is connected to the cathode of the antiparallel diode of the fourth power switch of the active T-type half-bridge.

[0029] The active T-type half-bridge has four connections: a switching voltage connection of the active T-type half-bridge, a positive connection of the active T-type half-bridge, a midpoint voltage connection of the active T-type half-bridge and a negative connection of the active T-type half-bridge.

[0030] The switching voltage terminal of the active T-type half-bridge is connected to the anode of the antiparallel diode of the first power switch of the active T-type half-bridge. The positive terminal of the active T-type half-bridge is connected to the cathode of the antiparallel diode of the first power switch of the active T-type half-bridge. The midpoint voltage terminal of the active T-type half-bridge is connected to the cathode of the antiparallel diode of the third power switch of the active T-type half-bridge. The negative terminal of the active T-type half-bridge is connected to the anode of the antiparallel diode of the fourth power switch of the active T-type half-bridge.

[0031] An embodiment of a passive T-type half-bridge ( Fig. 6) It has two diodes 62 and two power switches 61, which are connected as follows: The anode of the first diode of the passive T-type half-bridge is connected to the cathode of the antiparallel diode of the first power switch of the passive T-type half-bridge, the anode of the antiparallel diode of the first power switch of the passive T-type half-bridge is connected to the anode of the antiparallel diode of the second power switch of the passive T-type half-bridge, the anode of the first diode of the passive T-type half-bridge is connected to the cathode of the second diode of the passive T-type half-bridge.

[0032] The passive T-type half-bridge has four connections: a switching voltage connection of the passive T-type half-bridge, a positive connection of the passive T-type half-bridge, a midpoint voltage connection of the passive T-type half-bridge and a negative connection of the passive T-type half-bridge.

[0033] The switching voltage terminal of the passive T-type half-bridge is connected to the anode of the first diode of the passive T-type half-bridge. The positive terminal of the passive T-type half-bridge is connected to the cathode of the first diode of the passive T-type half-bridge. The midpoint voltage terminal of the passive T-type half-bridge is connected to the cathode of the antiparallel diode of the second power switch of the passive T-type half-bridge. The negative terminal of the passive T-type half-bridge is connected to the anode of the second diode of the passive T-type half-bridge.

[0034] One embodiment of an NPC (Neutral-Point Clamped) half-bridge ( Fig. 6a ) It has four circuit breakers 63 and two diodes 64, which are connected as follows: The anode of the antiparallel diode of the first power switch of the NPC half-bridge is connected to the cathode of the antiparallel diode of the second power switch of the NPC half-bridge and the cathode of the first diode; the anode of the antiparallel diode of the second power switch of the NPC half-bridge is connected to the cathode of the antiparallel diode of the third power switch of the NPC half-bridge; the anode of the antiparallel diode of the third power switch of the NPC half-bridge is connected to the anode of the second diode and the cathode of the antiparallel diode of the fourth power switch of the NPC half-bridge; the anode of the first diode of the NPC half-bridge is connected to the cathode of the second diode of the NPC half-bridge.

[0035] The NPC half-bridge has four connections: a switching voltage connection of the NPC half-bridge, a positive connection of the NPC half-bridge, a midpoint voltage connection of the NPC half-bridge and a negative connection of the NPC half-bridge.

[0036] The switching voltage terminal of the NPC half-bridge is connected to the anode of the antiparallel diode of the second power switch of the NPC half-bridge. The positive terminal of the NPC half-bridge is connected to the cathode of the antiparallel diode of the first power switch of the NPC half-bridge. The midpoint voltage terminal of the NPC half-bridge is connected to the anode of the first diode of the NPC half-bridge. The negative terminal of the NPC half-bridge is connected to the anode of the antiparallel diode of the fourth power switch of the NPC half-bridge. Examples of embodiments of the AC voltage filter stages:

[0037] A first embodiment of the AC voltage filter stage ( Fig. 7 ) It has the following components: one ( m +1)-phase common-mode filter choke 71, having m+1 windings, each having two terminals, m +1 filter coils 73, each having two terminals, 2 common-mode filter capacitors 74, each having two terminals, and m +1 filter capacitors 75, each having two terminals.

[0038] For 1 ≤ k ≤ m The following connections apply: the k -th input terminal of the first embodiment of the AC voltage filter stage with the first terminal of the k -th filter capacitor, the first connection of the k -th filter capacitor with the first connection of the k -th winding of the ( m +1)-phase common-mode filter choke, the second terminal of the k -th winding of the ( m +1)-phase common-mode filter choke with the first terminal of the k -ten filter coil, the second connection of the k -ten filter coil with the k-th output terminal of the first embodiment of the AC voltage filter stage.

[0039] The ( m +1)th input terminal of the first embodiment of the AC voltage filter stage is connected to the first terminal of the ( m +1)-th winding of the ( m +1)-phase common-mode filter choke, the first terminal of the ( m +1)-th filter capacitor and the first terminal of the second common-mode filter capacitor. The second terminals of all m +1 filter capacitors are connected to the first terminal of the first common-mode filter capacitor. The second terminal of the ( m +1)-th winding of the ( m +1)-phase common-mode filter choke is connected to the first terminal of the ( m +1)-th filter coil connected. The second connection of the ( m +1)-th filter coil is with the ( mThe second terminals of the two common-mode filter capacitors are connected to the ground terminal of the first embodiment of the AC filter stage.

[0040] For practical reasons, it may be useful to change the order of the ( m +1)-phase common-mode filter choke and the m +1 to swap the filter coils of the described series circuit. m +1 Filter coils can be magnetically coupled, e.g. in the sense of a common-mode or differential-mode choke.

[0041] Depending on the implementation, one or more components may be omitted: the ( m The +1)-phase common-mode filter choke 71 can be omitted, i.e. for 1 ≤ k ≤ m+1 It applies that the first connection of the k -th winding of the ( m +1)-phase common-mode filter choke with the second terminal of the k-th winding of the ( m +1)-phase common-mode filter choke is connected, individual or all filter coils 73 can be omitted, i.e., in the filter coil(s) concerned, the first terminal of the filter coil is connected to the second terminal of the filter coil, individual or all filter capacitors 75 can be removed from the circuit, one of the m +1 Filter capacitors 75 can be replaced by a short circuit, the first common-mode filter capacitor 74 can either be removed from the circuit or replaced by a short circuit, the second common-mode filter capacitor 74 can be removed from the circuit, combinations thereof, e.g. all filter coils can be omitted and the first common-mode filter capacitor removed from the circuit.

[0042] A second embodiment of the AC voltage filter stage ( Fig. 8 )It has the same components as the first embodiment of the AC filter stage and also the same connections between the components, except for one difference: the first connection of the ( m +1)-th filter capacitor of the second embodiment of the AC filter stage is not connected to the ( m +1)-th input terminal of the second embodiment of the AC filter stage, but with the second terminal of the ( m +1)-th winding of the ( m +1)-phase common-mode filter choke of the second embodiment of the AC voltage filter stage connected.

[0043] A third embodiment of the AC voltage filter stage ( Fig. 9 ) It has the same components as the first embodiment of the AC filter stage and also the same connections between the components, except for one difference: the first connection of the ( m+1)-th filter capacitor of the third embodiment of the AC filter stage is not connected to the ( m +1)-th input terminal of the third embodiment of the AC filter stage but with the ( m +1)-th output terminal of the third embodiment of the AC voltage filter stage is connected. Examples of designs for DC voltage blocks:

[0044] One embodiment of the switching block ( Fig. 10 ) It has the following components: two diodes 101, a switch 102 (e.g. the switch of a conventional relay) having two terminals and a common-mode filter capacitor 103 having two terminals.

[0045] The switch of the changeover block can assume the states 'on' or 'off'. In the 'on' state, the switch of the changeover block establishes an electrical connection between its two terminals. In the 'off' state, the electrical connection between the two terminals of the switch of the changeover block is broken.

[0046] The anode of the first diode in the switching block is connected to the cathode of the second diode, the first terminal of the switching block's switch, the first terminal of the switching block's common-mode filter capacitor, and the midpoint voltage terminal of the switching block's input terminal. The cathode of the first diode is connected to the positive terminal of the switching block's input terminal and the positive terminal of the switching block's output terminal. The anode of the second diode is connected to the negative terminal of the switching block's input terminal and the negative terminal of the switching block's output terminal. The second terminal of the switching block's switch is connected to the midpoint voltage terminal of the switching block's output terminal, and the second terminal of the common-mode filter capacitor is connected to the output terminal's ground terminal.

[0047] In an alternative implementation of the switching block, the common-mode filter capacitor is not present.

[0048] A first embodiment of the DC voltage filter block ( Fig. 11 ) It has the following components: a two-phase common-mode filter choke 115, comprising two windings, each comprising two terminals, two filter coils 116, each comprising two terminals, three common-mode filter capacitors 117, each comprising two terminals, and two filter capacitors 118, each comprising two terminals.

[0049] The first embodiment of the DC voltage filter block implements the following connections: The positive terminal of the input terminal of the first embodiment of the DC voltage filter block is connected to the first terminal of the first common-mode filter capacitor, the first terminal of the first filter capacitor, and the first terminal of the first winding of the two-phase common-mode filter choke. The midpoint voltage terminal of the input terminal of the first embodiment of the DC voltage filter block is connected to the first terminal of the second common-mode filter capacitor, the second terminal of the first filter capacitor, and the second terminal of the second filter capacitor. The negative terminal of the input terminal of the first embodiment of the DC filter block is connected to the first terminal of the third common-mode filter capacitor, the first terminal of the second filter capacitor, and the first terminal of the second winding of the two-phase common-mode filter choke. The second terminal of the first winding of the two-phase common-mode filter choke is connected to the first terminal of the first filter coil. The second terminal of the second winding of the two-phase common-mode filter choke is connected to the first terminal of the second filter coil. The second terminal of the first filter coil is connected to the positive terminal of the output terminal of the first embodiment of the DC filter block. The second terminal of the second filter coil is connected to the negative terminal of the output terminal of the first embodiment of the DC filter block.The second terminals of all common-mode filter capacitors are connected together and form the ground connection of the first embodiment of the DC voltage filter block. The midpoint voltage connection of the output terminal of the first embodiment of the DC voltage filter block is omitted.

[0050] Another variant of this DC voltage filter block occurs when the described series circuits of filter coils and windings of the two-phase common-mode filter choke are reversed.

[0051] Depending on the implementation, one or more components may be omitted: The two-phase common-mode filter choke can be omitted, i.e. for 1 ≤ k ≤ 2, it is held that the first connection of the k -th winding with the second connection of the k-ten winding is connected, individual or all filter coils can be omitted, i.e., in the relevant filter coil(s), the first terminal of the filter coil is connected to the second terminal of the filter coil; individual, several, or all common-mode filter capacitors can be omitted, i.e., the relevant common-mode filter capacitor(s) are removed from the circuit; combinations thereof, e.g., all filter coils and all common-mode filter capacitors can be omitted.

[0052] A second embodiment of the DC voltage filter block ( Fig. 12 ) It has the following components: a three-phase common-mode filter choke 125, comprising three windings, each comprising two terminals, three filter coils 126, each comprising two terminals, three common-mode filter capacitors 127, each comprising two terminals, and two filter capacitors 128, each comprising two terminals.

[0053] The second embodiment of the DC voltage filter block implements the following connections: The positive terminal of the input terminal of the second embodiment of the DC filter block is connected to the first terminal of the first common-mode filter capacitor, the first terminal of the first filter capacitor, and the first terminal of the first winding of the three-phase common-mode filter choke. The midpoint voltage terminal of the input terminal of the second embodiment of the DC filter block is connected to the first terminal of the second common-mode filter capacitor, the second terminal of the first filter capacitor, the second terminal of the second filter capacitor, and the first terminal of the second winding of the three-phase common-mode filter choke.The negative terminal of the input terminal of the second embodiment of the DC filter block is connected to the first terminal of the third common-mode filter capacitor, the first terminal of the second filter capacitor, and the first terminal of the third winding of the three-phase common-mode filter choke. The second terminal of the first winding of the three-phase common-mode filter choke is connected to the first terminal of the first filter coil. The second terminal of the second winding of the three-phase common-mode filter choke is connected to the first terminal of the second filter coil. The second terminal of the third winding of the three-phase common-mode filter choke is connected to the first terminal of the third filter coil. The second terminal of the first filter coil is connected to the positive terminal of the output terminal of the second embodiment of the DC filter block.The second terminal of the second filter coil is connected to the midpoint voltage terminal of the output terminal of the second embodiment of the DC filter block. The second terminal of the third filter coil is connected to the negative terminal of the output terminal of the second embodiment of the DC filter block. The second terminals of all common-mode filter capacitors are connected together and form the ground terminal of the second embodiment of the DC filter block.

[0054] Another variant of this DC filter block occurs when the series connections of filter coils and windings of the three-phase common-mode filter choke are reversed.

[0055] Depending on the implementation, one or more components may be omitted: The three-phase common-mode filter choke can be omitted, i.e. for 1 ≤ k ≤ 3, it is assumed that the first connection of the k-th winding with the second connection of the k -ten winding is connected, individual or all filter coils can be omitted, i.e., in the relevant filter coil(s), the first terminal of the filter coil is connected to the second terminal of the filter coil; individual, several, or all common-mode filter capacitors can be omitted, i.e., the relevant common-mode filter capacitor(s) are removed from the circuit; combinations thereof, e.g., all filter coils and all common-mode filter capacitors can be omitted.

[0056] A third embodiment of the DC voltage filter block ( Fig. 13 )The device comprises a capacitor 135, having two terminals, and two common-mode filter capacitors 136, each having two terminals. The first terminal of the capacitor is connected to the positive terminals of the input and output terminals of the third embodiment of the DC voltage filter block. The second terminal of the capacitor is connected to the negative terminals of the input and output terminals of the third embodiment of the DC voltage filter block. The first terminal of the first common-mode filter capacitor is connected to the positive terminals of the input and output terminals of the third embodiment of the DC voltage filter block. The first terminal of the second common-mode filter capacitor is connected to the negative terminals of the input and output terminals of the third embodiment of the DC voltage filter block.The second terminals of the two common-mode filter capacitors are connected together and form the ground connection of the third embodiment of the DC voltage filter block. The midpoint voltage connections of the input and output terminals of the third embodiment of the DC voltage filter block are omitted.

[0057] A fourth embodiment of the DC voltage filter block ( Fig. 14 )The device comprises two capacitors 141, each having two terminals, and three common-mode filter capacitors 142, each having two terminals. The first terminal of the first capacitor is connected to the positive terminals of the input and output terminals of the fourth embodiment of the DC filter block. The second terminal of the first capacitor is connected to the first terminal of the second capacitor and the midpoint terminals of the input and output terminals of the fourth embodiment of the DC filter block. The second terminal of the second capacitor is connected to the negative terminals of the input and output terminals of the fourth embodiment of the DC filter block. The first terminal of the first common-mode filter capacitor is connected to the positive terminals of the input and output terminals of the fourth embodiment of the DC filter block.The first terminal of the second common-mode filter capacitor is connected to the midpoint voltage terminals of the input and output terminals of the fourth embodiment of the DC filter block. The first terminal of the third common-mode filter capacitor is connected to the negative terminals of the input and output terminals of the fourth embodiment of the DC filter block. The second terminals of the three common-mode filter capacitors are connected together and form the ground connection of the fourth embodiment of the DC filter block.

[0058] A DC voltage filter block with active voltage balancing ( Fig. 15 ) It has the following components: two capacitors 151, each having two terminals, three common-mode filter capacitors 152, each having two terminals, a half-bridge 153 with two voltage levels, having a positive terminal, a switching voltage terminal and a negative terminal, and a filter coil 154, having two terminals.

[0059] The first terminal of the first capacitor is connected to the positive terminal of the dual-level half-bridge and the positive terminals of the input and output terminals of the DC-DC filter block with active voltage balancing. The second terminal of the first capacitor is connected to the first terminal of the second capacitor, the first terminal of the filter inductor, and the midpoint voltage terminal of the input terminals of the DC-DC filter block with active voltage balancing. The second terminal of the second capacitor is connected to the negative terminal of the dual-level half-bridge and the negative terminals of the input and output terminals of the DC-DC filter block with active voltage balancing. The second terminal of the filter inductor is connected to the switching voltage terminal of the dual-level half-bridge.The first terminal of the first common-mode filter capacitor is connected to the positive terminals of the input and output terminals of the DC-DC filter block with active voltage balancing. The first terminal of the second common-mode filter capacitor is connected to the midpoint voltage terminal of the input terminal of the DC-DC filter block with active voltage balancing. The first terminal of the third common-mode filter capacitor is connected to the negative terminals of the input and output terminals of the DC-DC filter block with active voltage balancing. The second terminals of the three common-mode filter capacitors are connected together to form the ground connection of the DC-DC filter block with active voltage balancing. The midpoint voltage connection of the output terminal of the DC-DC filter block with active voltage balancing is omitted. Examples of embodiments of the DC-DC converter block

[0060] A first embodiment of the DC-DC converter ( Fig. 16) It has the following components: two DC voltage converters 161, 162, each having an input terminal block, having a positive terminal and a negative terminal, and an output terminal block, having a positive terminal and a negative terminal, an input-side relay 163, having a control coil 1630, having two control terminals, and two changeover switches 1631, 1632, each having a changeover terminal and two switch terminals, and an output-side relay 164, having a control coil 1640 and two changeover switches 1641, 1642, each having a changeover terminal and two switch terminals.

[0061] Each changeover switch 1631, 1632, 1641, 1642 can have two states. In the first state, the changeover terminal of the changeover switch is connected to the first switch terminal of the changeover switch, and the second switch terminal of the changeover switch is not connected. In the second state, the changeover terminal of the changeover switch is connected to the second switch terminal of the changeover switch, and the first switch terminal of the changeover switch is not connected.

[0062] Each relay 163, 164 can have two states. In the first state, both relay switches are in the first position. In the second state, both relay switches are in the second position. Activating a desired relay state is achieved by appropriately adjusting a control voltage applied to the two control terminals of the relay's control coil.

[0063] The following connections apply to the first embodiment of the DC-DC converter: The positive terminal of the input terminal block of the DC-DC converter is connected to the positive terminal of the input terminal block of the first DC-DC converter and to the first switch terminal of the second changeover switch of the input-side relay 163. The midpoint voltage terminal of the input terminal block of the DC-DC converter is connected to the second switch terminal of the first changeover switch 1631 of the input-side relay 163 and to the second switch terminal of the second changeover switch 1632 of the input-side relay. The negative terminal of the input terminal block of the DC-DC converter is connected to the negative terminal of the input terminal block of the second DC-DC converter and to the first switch terminal of the first changeover switch 1631 of the input-side relay. The changeover terminal of the first changeover switch 1631 of the input-side relay is connected to the negative terminal of the input terminal block of the first DC-DC converter.The negative terminal of the input terminal block of the DC-DC converter is connected to the negative terminal of the input terminal block of the second DC-DC converter and to the first switch terminal of the first switch 1631 of the input-side relay. The changeover terminal of the first switch 1631 of the input-side relay is connected to the negative terminal of the input terminal block of the first DC-DC converter. The changeover terminal of the second switch 1632 of the input-side relay is connected to the positive terminal of the input terminal block of the second DC-DC converter.The positive terminal of the output terminal block of the DC-DC converter is connected to the positive terminal of the output terminal block of the first DC-DC converter 161 and to the first switch terminal of the second changeover switch 1642 of the output-side relay. The midpoint voltage terminal of the output terminal block of the DC-DC converter is connected to the second switch terminal of the first changeover switch 1641 of the output-side relay and to the second switch terminal of the second changeover switch 1642 of the output-side relay. The negative terminal of the output terminal block of the DC-DC converter is connected to the negative terminal of the output terminal block of the second DC-DC converter 162 and to the first switch terminal of the first changeover switch 1641 of the output-side relay. The changeover terminal of the first changeover switch 1641 of the output-side relay is connected to the negative terminal of the output terminal block of the first DC-DC converter.The changeover terminal of the second changeover switch 1642 of the output-side relay is connected to the positive terminal of the output terminal block of the second DC voltage converter.

[0064] The described circuit allows all combinations of input- and output-side parallel or series connections of the two DC voltage converters, whereby the sub-variants with output-side series connection are not according to the invention: These can be achieved solely by switching the relays: switching the input-side relay from the first to the second state halves the output voltage, and switching the output-side relay from the first to the second state doubles the output voltage. This can be technically advantageous for the operation of the universal multi-phase converter topology, for example, when single-phase operation is used instead of multi-phase operation.

[0065] A second embodiment of the DC-DC converterThis results when the first embodiment of the DC-DC converter is implemented without an output-side relay. Sub-variants exist here, namely the series or parallel connection of the two DC-DC converters on the output side. Switching the input-side relay from the first to the second state results in a halving of the output voltage.

[0066] A third embodiment of the DC-DC converter This results when the first embodiment of the DC-DC converter is implemented without an input-side relay. Sub-variants exist here, involving the input-side connection of the two DC-DC converters in series or parallel. Switching the output-side relay from the first to the second state results in a doubling of the output voltage.

[0067] A fourth embodiment of the DC-DC converterThis results when the first embodiment of the DC-DC converter is implemented without an input-side relay and without an output-side relay. There are four sub-variants of input- and output-side series or parallel connections of the two DC-DC converters. In the case of input- and output-side parallel connections of the two DC-DC converters, one DC-DC converter can be removed from the circuit.

[0068] One embodiment of the ( m +1)-phase common-mode filter choke points m+1 Windings 171, 172, 173, 174, 175, 176, each with two terminals. For 1 ≤ k ≤ m applies: the k -th winding of the ( m The +1)-phase common-mode filter choke serves for common-mode filtering of the components in the k -th phase of the universal multiphase converter topology common-mode disturbances present. The ( m +1)th winding of the ( mThe +1)-phase common-mode filter choke serves for additional common-mode filtering during single-phase operation of the universal multi-phase converter topology and prevents, when using a magnetic core for the realization of the ( m +1)-phase common-mode choke, that the single-phase operation of the universal multi-phase converter topology leads to the saturation of the magnetic core of the ( m +1)-phase common-mode choke. Each winding can be implemented either as a single, continuous winding package or through suitable series and / or parallel connections of several winding packages. The individual winding packages can be geometrically distributed as appropriate. For a technically feasible implementation, all m+1 windings of the ( m +1)-phase common-mode filter chokes typically have the same number of turns and the same winding directions. In single-phase operation of the universal multi-phase converter topology, the ( m+1)th winding of the ( m +1)-phase common-mode filter choke loaded with a current which is the sum of all currents through the first m windings of the ( m +1)-phase common-mode filter choke corresponds to.

[0069] By using one or more magnetic cores, increased inductance values ​​can be achieved between the respective terminals of each winding of the ( m +1)-phase common-mode filter choke. In practice, toroidal cores are usually used for this purpose ( Figs. 17 and 18 ), but in principle any kernel form can be used, e.g. E-kernels, U-kernels, UI-kernels or planar kernels.

[0070] A first possible embodiment of the ( m +1)-phase common-mode filter choke is in Fig. 17 shown, with a first AC winding 171, a second AC winding 172, m -3 further AC windings 173, one m-ten AC winding 175 and a return conductor winding 176, on a common magnetic core 170. Here, the requirements for the realization of the first m Windings 171-175 required wires with the same conductor cross-sections A Cu,1. The one for the ( m +1)-th winding 176 wire used shows the m -fold effective conductor cross-section ( A Cu,m+1 = m A Cu,1 ) . In Fig. 17 will the ( m +1)th winding is realized as a connected winding package.

[0071] A second possible embodiment of the ( m +1)-phase common-mode filter choke is in Fig. 18 shown here. The first steps are indicated here. m The windings required wires with the same conductor cross-sections. A Cu,1 on. The one for the ( m +1)-th winding used wire has the m -fold effective conductor cross-section ( A Cu,m+1 = m A Cu,1 ). Unlike Fig. 17 will be in Fig. 18 the ( m +1)-th winding realized as a distributed winding package, comprising a first, second, third to m -th return conductor winding 181, 182, 183, 185. Further AC voltage and return conductor windings are designated 174, 184.

[0072] In Fig. 19 and Fig. 20 These are cross-sectional drawings of possible conductor arrangements. m+1 windings of the ( m +1)-phase common-mode filter choke shown in the core window of E-cores, U-cores, UI-cores or planar cores. Due to the increased conductor cross-section requirement for a technically feasible implementation, ( m +1)th winding fills the ( m+ 1) The first winding occupies the first half of the core window available to all windings, and the remaining m windings share the second half of the available core window equally. Examples of embodiments of the universal multiphase inverter topology

[0073] One embodiment of the universal three-phase converter with two voltage levels ( Fig. 21 ) is not according to the invention, and is based on the embodiment of the universal multiphase converter topology with DC-DC converter block and features m = 3 and the following assemblies: Each of the three half-bridges 2111, 2112, 2113 of the power section 21 is realized by the in Fig. 3 The illustrated embodiment of the half-bridge with two voltage levels, three AC voltage filter stages 22, ∘ the first AC voltage filter stage 2121 is formed by the first embodiment of the AC voltage filter stage made of Fig. 7 realized with the following modifications: the four-phase common-mode filter choke is omitted, the fourth filter coil is omitted, the fourth filter capacitor is replaced by a short circuit, and the two common-mode filter capacitors are removed from the circuit; the second AC filter stage 2122 is replaced by the first embodiment of the AC filter stage. Fig. 7realized, ∘ the third AC voltage filter stage 2123 is realized by the first embodiment of the AC voltage filter stage made of Fig. 7 realized, with the following modifications: all four filter coils are omitted, all four filter capacitors are removed from the circuit, and the two common-mode filter capacitors are removed from the circuit; three DC voltage blocks: ∘ the first DC voltage block 2131 is replaced by the embodiment of the switching block made of Fig. 10 realized, ∘ the second DC voltage block 2132 is made up of the first embodiment of the DC voltage filter block Fig. 11 realized, with the following modifications: the two filter coils are omitted and the three common-mode filter capacitors are removed from the circuit; the third DC voltage block 2133 is replaced by the fourth embodiment of the DC voltage filter block. Fig. 14realized with the following adaptation: the three common-mode filter capacitors are removed from the circuit, the DC voltage converter block 24 is realized by the second embodiment of the DC voltage converter, with output-side parallel connection of the two DC voltage converters. How it works:

[0074] Operation as a conventional three-phase inverter: ∘ The power switches of the three half-bridges are controlled appropriately for operation as a three-phase inverter with two voltage levels; the control, e.g., of the inverter's output voltage, is exactly the same as in a conventional three-phase inverter with two voltage levels, ∘ Switches of the transfer switch block are closed, ∘ Input-side relay of the DC-DC converter block is in the second state. Operation as a conventional single-phase inverter: ∘ Switches of the transfer switch block are open, ∘ Power switches of the three half-bridges are operated synchronously so that the electrical potentials at their switching voltage terminals assume the same value at all times; the control, e.g.,The output voltage of the inverter is controlled in exactly the same way as in a conventional single-phase inverter with two voltage levels. Compared to operation as a conventional three-phase inverter, the circuit operates more efficiently at half the DC link voltage (i.e., the voltage between the positive and negative terminals of the power section); therefore, to maintain the inverter's output voltage, the input-side relay of the DC-DC converter block is operated in the first state.

[0075] A first embodiment of the universal three-phase converter with active T-type half-bridges ( Fig. 22 ) is according to the invention, and is based on the embodiment of the universal multiphase converter topology with DC-DC converter block and has m = 3 and the following assemblies: Each of the three half-bridges is realized by the in Fig. 5The illustrated embodiment of the active T-type half-bridge comprises four AC filter stages, ∘ the first AC filter stage is formed by the first embodiment of the AC filter stage made of Fig. 7 realized with the following modifications: the four-phase common-mode filter choke is omitted, the fourth filter coil is omitted, the fourth filter capacitor is replaced by a short circuit, and the two common-mode filter capacitors are removed from the circuit; the second AC filter stage is replaced by the first embodiment of the AC filter stage. Fig. 7 This is implemented with the following modifications: the fourth filter capacitor is replaced by a short circuit and the two common-mode filter capacitors are removed from the circuit; the third AC filter stage is replaced by the first embodiment of the AC filter stage. Fig. 7Realized with the following modifications: the four-phase common-mode filter choke is omitted, all four filter coils are omitted, the first common-mode filter capacitor is replaced by a short circuit, and the second common-mode filter capacitor is removed from the circuit; the fourth AC filter stage is replaced by the first embodiment of the AC filter stage. Fig. 7 Realized with the following modifications: all four filter coils are omitted, all four filter capacitors are removed from the circuit, and the two common-mode filter capacitors are removed from the circuit. Three DC voltage blocks: ∘ the first DC voltage block is replaced by the embodiment of the switching block made of Fig. 10 realized, ∘ the second DC voltage block is made up of the first embodiment of the DC voltage filter block Fig. 11realized with the following modifications: the two filter coils are omitted and the three common-mode filter capacitors are removed from the circuit; the third DC voltage block is replaced by the fourth embodiment of the DC voltage filter block. Fig. 14 realized with the following modification: the three common-mode filter capacitors are removed from the circuit, the DC-DC converter block is realized by the second embodiment of the DC-DC converter, with the two DC-DC converters connected in parallel on the output side. How it works:

[0076] Operation as a three-phase inverter: ∘ The power switches of the three half-bridges are controlled appropriately for operation as a three-phase inverter with three voltage levels; the control, e.g., of the inverter's output voltage, is exactly the same as in a conventional three-phase inverter with three voltage levels, ∘ Switches of the transfer switch block are closed, ∘ Input-side relay of the DC-DC converter block is in the second state. Operation as a single-phase inverter: ∘ Switches of the transfer switch block are open, ∘ Power switches of the three half-bridges are operated synchronously so that the electrical potentials at their switching voltage terminals assume the same value at all times; the control, e.g.,The output voltage of the inverter is controlled in exactly the same way as in a conventional single-phase inverter with two voltage levels. Compared to operation as a conventional three-phase inverter, the circuit operates more efficiently at half the DC link voltage (i.e., the voltage between the positive and negative terminals of the power section); therefore, to maintain the inverter's output voltage, the input-side relay of the DC-DC converter block is operated in the first state.

[0077] A second embodiment of the universal three-phase converter with active T-type half-bridges ( Fig. 23 ) is not according to the invention, and is based on the embodiment of the universal multiphase converter topology without a DC-DC converter block and has m = 3 and the following assemblies: Each of the three half-bridges is realized by the in Fig. 5The illustrated embodiment of the active T-type half-bridge has four AC filter stages: ∘ the first AC filter stage is formed by the first embodiment of the AC filter stage from Fig. 7 realized with the following modifications: the four-phase common-mode filter choke is omitted, the fourth filter coil is omitted, the fourth filter capacitor is replaced by a short circuit, and the two common-mode filter capacitors are removed from the circuit; the second AC filter stage is replaced by the first embodiment of the AC filter stage. Fig. 7 This is implemented with the following modifications: the fourth filter capacitor is replaced by a short circuit, and the two common-mode filter capacitors are removed from the circuit. The third AC filter stage is replaced by the first embodiment of the AC filter stage. Fig. 7This is implemented with the following modifications: the four-phase common-mode filter choke is omitted, all four filter coils are omitted, the first common-mode filter capacitor is replaced by a short circuit, and the second common-mode filter capacitor is removed from the circuit. The fourth AC filter stage is replaced by the first embodiment of the AC filter stage. Fig. 7 Realized with the following modifications: all four filter coils are omitted, all four filter capacitors are removed from the circuit, and the two common-mode filter capacitors are removed from the circuit. Two DC voltage blocks: ∘ the first DC voltage block is replaced by the first embodiment of the DC voltage filter block made of Fig. 12This is implemented with the following modifications: the three filter coils are omitted, the first common-mode filter capacitor is removed from the circuit, and the third common-mode filter capacitor is removed from the circuit. The third DC voltage block is replaced by the DC voltage filter block with active voltage balancing. Fig. 15 realized. How it works:

[0078] Operation as a three-phase inverter: ∘ The power switches of the three half-bridges are controlled appropriately for operation as a three-phase inverter with three voltage levels; the regulation, e.g., of the inverter's output voltage, is carried out exactly the same as in a conventional three-phase inverter with three voltage levels. Operation as a conventional single-phase inverter: ∘ The power switches of the three half-bridges are operated synchronously so that the electrical potentials at their switching voltage terminals assume the same value at all times; the regulation, e.g., of the inverter's output voltage, is carried out exactly the same as in a conventional single-phase inverter with three voltage levels.

[0079] Compared to the embodiment of the universal three-phase converter with two voltage levels ( Fig. 21 ) and the first embodiment of the universal three-phase converter with active T-type half-bridges ( Fig. 22) has the second embodiment of the universal three-phase converter with active T-type half-bridges ( Fig. 23 The advantage is that the switching block and DC-DC converter block are eliminated, but the disadvantage is that the DC filter block with active voltage balancing is required for practical operation. While the DC filter block with active voltage balancing can theoretically be omitted, comparatively high capacitance values ​​for the filter capacitors of the first DC block would then be necessary for practical operation as a single-phase converter.

Claims

1. Multi-phase converter topology for the transmission of electrical energy from an alternating voltage input (25) having m grid phase connections (28) to a DC voltage output (26) or vice versa, the multi-phase converter comprising a power part (21) comprising half-bridges (211, 212, 213) for switching currents, each of the half-bridges comprising a positive connection and a negative connection, an alternating voltage filter (22) connected between the power part (21) and the alternating voltage input (25), the alternating voltage filter comprising at least one alternating voltage filter stage (221, 222, 223) having m+1 input connections, m+1 output connections; one or more DC voltage blocks (23) connected between the power part (21) and the DC voltage output (26) for filtering DC voltages, each DC voltage block comprising an input terminal block having a positive connection and a negative connection, and an output terminal block having a positive connection and a negative connection; and a DC / DC converter block (24); the positive connection of each half-bridge of the power part (21) being connected to the positive connection of the input terminal block of the first DC voltage block, and the negative connection of each half-bridge of the power part (21) being connected to the negative connection of the input terminal block of the first DC voltage block, in single-phase operation, the m grid phase connections (28) being connected in parallel to one another and forming a first phase connection for the connection of a single-phase alternating voltage, and a neutral conductor connection of the alternating voltage filter forming a neutral conductor connection (27) of the alternating voltage input (25) and a second phase connection for the connection of the single-phase alternating voltage, characterized in that: the at least one alternating voltage filter stage comprises a ground connection; and the half-bridges (2111, 2112, 2113) of the power part (211) form a converter having three voltage levels; and the DC / DC converter block (24) has two DC / DC converters (161, 162), the inputs of which are selectively switchable between a series and a parallel arrangement, and the outputs of which, connected in parallel, form the DC voltage output (26); and the multi-phase converter topology has a control designed to selectively operate the multi-phase converter topology in multi-phase operation having three voltage levels or in single-phase operation having two voltage levels, the voltage between the positive and negative connections of the power part being halved in single-phase operation compared to multi-phase operation, and the inputs of the two DC / DC converters (161, 162) are switched to the series arrangement in multi-phase operation and to the parallel arrangement in single-phase operation.

2. Multi-phase converter topology according to claim 1, wherein the alternating voltage filter (22) has at least one (m+1)-phase common-mode filter choke, which does not saturate during single-phase operation of the multi-phase converter topology.

3. Multi-phase converter topology according to claim 2, wherein all m+1 windings of the at least one (m+1)-phase common-mode filter choke have the same number of turns and the same winding direction.

4. Multi-phase converter topology according to claim 3, wherein wires present in the first m windings (171 ... 175) have the same first conductor cross section, and a wire present in the (m+1)-th winding (176; (181 ... 185) has a conductor cross section which is m-times the cross section of the first conductor.

5. Multi-phase converter topology according to any of the preceding claims, wherein: the power part (21) comprises a midpoint voltage connection which is connected to a midpoint voltage connection of the alternating voltage filter (22) and to a midpoint voltage connection of the input terminal block, the (m+1)-th output connection of a first alternating voltage filter stage (221) forms the midpoint voltage connection of the alternating voltage filter, and the (m+1)-th input connection of the final alternating voltage filter stage forms the neutral conductor connection of the alternating voltage filter.