Abstract: A converter circuit is specified for switching of a multiplicity of switching voltage levels, which have n first switching groups (1.1, . . . , 1.n) for each phase (R, S, T), with the n-th first switching group (1.n) being formed by a first drivable bidirectional power semiconductor switch (2) and a second drivable bidirectional power semiconductor switch (3), and with the first first switching group (1.1) to the (n?1)-th switching group (1.(n?1)) each being formed by a first drivable bidirectional power semiconductor switch (2) and a second drivable bidirectional power semiconductor switch (3), and by a capacitor (4) which is connected to the first and second drivable bidirectional power semiconductor switches (2, 3) with each of the n first switching groups (1.1, . . . , 1.n) being connected in a linked form to the respectively adjacent first switching group (1.1, . . . , 1.n), and with the first and the second drivable bidirectional power semiconductor switches (2, 3) in the first first switching group (1.

Abstract: A converter circuit having a first and a second converter element is specified, with each converter element having a DC voltage circuit and in each case one converter element phase (u1, v1, w1) of the first converter element being connected to a respective converter element phase (u2, v2, w2) of the second converter element. Furthermore, a transformer is provided, with the secondary windings of the transformer being connected to the connected converter element phases (u1, v1, w1, u2, v2, w2) of the first and second converter elements.

Abstract: A converter circuit is specified for at least one phase (R, Y, B), which converter circuit has a first switching group system which is provided for each phase (R, Y, B) and has a first main switching group which is formed by a power semiconductor switch and by a capacitor which is connected to the power semiconductor switch, and which first switching group system has at least one intermediate switching group which is formed by two series-connected power semiconductor switches which can be driven and by a capacitor, with the or one intermediate switching group being connected to the first main switching group. Furthermore, the first switching group system has a second main switching group which is formed by a power semiconductor switch, with the or an intermediate switching group being connected to the second main switching group.

Abstract: A converter circuit is specified for switching a large number of switching voltage levels, which has n first switching groups for each phase, with the n-th first switching group being formed by a first power semiconductor switch and a second power semiconductor switch, and with the first first switching group to the-th switching group each being formed by a first power semiconductor switch and a second power semiconductor switch and by a capacitor, which is connected to the first and second power semiconductor switches, with each of the n first switching groups being connected in series to the respectively adjacent first switching group, and with the first and the second power semiconductor switches in the first first switching group being connected to one another.

Abstract: A method and apparatus for the voltage maintenance of an electrical AC voltage supply network comprising a partial converter system, which has a first branch pair and a second branch pair connected in parallel therewith and an electrical energy store connected in parallel with the branch pairs. Each branch pair is formed from two series-connected driveable power semiconductor switches, each with a diode reverse-connected in parallel, and the junction point of the power semiconductor switches of the first branch pair forming a first terminal and the junction point of the power semiconductor switches of the second branch pair forming a second terminal. The partial converter system has a third branch pair connected in parallel with the first and second branch pairs. The junction point of the power semiconductor switches of the third branch pair forms a third terminal.

Abstract: An apparatus for the voltage maintenance of an electrical AC voltage supply network (1) is specified, which comprises a partial converter system (2), which has a first branch pair (13) and a second branch pair (14) connected in parallel therewith and an electrical energy store (4) connected in parallel with the branch pairs (13, 14), each branch pair (13, 14) being formed from two series-connected driveable power semiconductor switches with in each case a diode reverse-connected in parallel with each power semiconductor switch, and the junction point of the power semiconductor switches of the first branch pair (13) forming a first terminal (9) of the partial converter system (2) and the junction point of the power semiconductor switches of the second branch pair (14) forming a second terminal (5) of the partial converter system (2).

Abstract: A converter system for increasing a DC voltage is specified, which converter system is formed by at least one converter system element (2) having an input-side DC circuit (3) connected to a first voltage inverter (5), and by a center point connection (4), which is formed by at least two series-connected DC capacitances (21a; 21b). The center point connection (4) is connected to a first connection (22a) of the primary winding (8) of a transformer (7), with the output of the first voltage inverter (5) being connected to a second connection (22b) of the primary winding (8) of the transformer (7), and the secondary winding (9) of the transformer (7) being connected to the input of an output-side converter (6) which is provided for producing an output-side DC voltage.

Abstract: The power semiconductor device has a pn junction between two power electrodes (2, 3). A control electrode (4) is arranged in the region of one of the two power electrodes (3). A current can be fed in via the control electrode, which current can be used to raise the current through the power electrodes. As a result, the reverse current can be raised in the blocking state of the device.

Abstract: A circuit for transmitting real power from a DC voltage side to AC voltage-side connections has a first power converter (4) with load connections (5) connected in series with second power converters (7) having a lower intermediate-circuit capacitor voltage. This allows finer voltage graduation of a sum voltage at the AC voltage-side connections (10). Voltages of intermediate-circuit capacitances of power converters (4, 7) and a common-mode voltage of the AC voltage-side connections can be jointly regulated. The intermediate-circuit capacitor voltages can be kept essentially constant. The second power converters (7) can interchange real power with a load (11) and the first power converter (4). Changes in the intermediate-circuit capacitor voltages can be calculated in advance using a model of the converter. The common-mode voltage can be selected to minimize a weighted sum of the squares of the errors between the intermediate-circuit capacitor voltages and the respective nominal values.

Abstract: The circuit arrangement for transmitting real power from a DC voltage side to AC voltage-side connections has a first power converter (4) with load connections (5), in series with each of which second power converters (7) with a lower intermediate-circuit capacitor voltage are connected. This makes it possible to achieve finer voltage graduation of a sum voltage at the AC voltage-side connections (10). According to the invention, the second power converters (7) do not have their own real power supplies. There is thus no need for the previously used rectifiers for supplying the second power converters (7).

Abstract: A converter system for increasing a DC voltage is specified, which converter system is formed by at least one converter system element (2) having an input-side DC circuit (3) connected to a first voltage inverter (5), and by a center point connection (4), which is formed by at least two series-connected DC capacitances (21a; 21b). The center point connection (4) is connected to a first connection (22a) of the primary winding (8) of a transformer (7), with the output of the first voltage inverter (5) being connected to a second connection (22b) of the primary winding (8) of the transformer (7), and the secondary winding (9) of the transformer (7) being connected to the input of an output-side converter (6) which is provided for producing an output-side DC voltage.

Abstract: A semiconductor module having a base element, at least one insulation element arranged on the base element, and at least one semiconductor element arranged on the insulation element. The insulation element has a metal layer on one side and another metal layer on the opposite side. At least one of the metal layers is curved or has curved portions. As a result, it is possible to minimize excessive field increases in the edge zones and increase the dielectric strength of the semiconductor module.

Abstract: A three-point converter with NPC diodes disposed between bridge halves and a center tap of an intermediate circuit is proposed. A decoupling network is provided for the upper bridge half, a first input of which decoupling network is connected to a positive pole of the intermediate circuit and a first output of the decoupling network is connected to a positive pole of the three-point converter. Furthermore, provision is made of a further decoupling network for the lower bridge half, a first input of the further decoupling network is connected to a negative pole of the intermediate circuit and a first output of the further decoupling network is connected to a negative pole of the three-point converter. The remaining inputs of both of the decoupling networks are connected to the center tap of the intermediate circuit. The remaining outputs of both of the decoupling networks are connected via the NPC diodes to the upper and lower bridge halves.

Abstract: A method for operating a power electronic circuit having a first power convertor and at least one second power convertor is specified. The pulse duration-modulated driving of the switches of the circuit arrangement is effected according to a comparison of a reference oscillation with a carrier oscillation. According to the invention, a component of a third harmonic is admixed with the reference oscillation over virtually the entire drive-level range, in particular including low drive-level rates in the range from 20% to approximately 87%. It is also possible to admix a corresponding component of a ninth harmonic in the drive-level range from 20% to approximately 33%. This results in a low clock frequency for the first power convertor and the second power convertor need not have a feedback capability. (FIG.

Abstract: An a.c. machine (7) with, connected in parallel thereto, a capacitor bank (CR, CS, CT), which are fed by a converter (1-4) with a d.c. intermediate circuit, form a resonant system which is excited by the rectangular current of an inverter (4) of the converter. In this case, there is superimposition of the fundamentals and the normal harmonics in the machine voltage and in the machine current of an additional harmonic with the frequency of the resonance point. In the lower speed range of the a.c. machine (7), this excitation is eliminated by an optimum operating sequence of current gaps, which are generated inside a current block by means of a quenching circuit (3). Current gaps are generated at the start and end of each current block for the purpose of damping the 11th and 13th harmonic, and in the middle of the current block for the purpose of damping the 7th harmonic. A turn-on angle basic value signal (.alpha..sub.M) is modified by a turn-on angle differential signal (.DELTA..alpha..sub.

Abstract: In circuits with self-commutation such as, for example in inverters (4) for feeding an asynchronous machine (7), a short-time turn-off current impulse is taken from a turn-off capacitor (C1) of a turn-off or common turn-off circuit (3) for interrupting the thyristor current of the inverter. The turn-off circuit (3) connected to the direct-current side (8, 9) of the inverter (4) exhibits a first series circuit of the turn-off capacitor (C1) and a first electrical valve (T2, D2). In a branch in parallel with the turn-off capacitor (C1), a ring-around reactor (L1) with an inductance of 0.1 mH is connected in series with a second thyristor (T1). A further third thyristor (T3) is connected in antiparallel with the second thyristor (T1). A ring-around process initiated by the firing of the second thyristor (T1) is interrupted after a half period. After a freely selectable time, the third thyristor (T3) can be fired and the full resonance cycle can be concluded.