Converter, electrical polyphase system and method
View Patent ↗An electric machine has a multiplicity of windings having a first terminal and a second terminal. At least one node exists to which one of the two terminals of a respective winding from the multiplicity of windings is electrically connected. The corresponding other terminal of a respective winding from the multiplicity of windings is electrically connected to a phase terminal, and to a modular multilevel converter that has a multiplicity of individual modules that are connected up in series to form a ring. At least one tap can be arranged between two respective adjacent individual modules and provides a phase terminal to which the first or the second terminal of a winding from the multiplicity of windings of the electric machine is electrically connected. A number of taps of the modular multilevel converter corresponds exactly to a number of windings from the multiplicity of windings of the electric machine.
1. A modular multilevel converter comprising:
at least one control unit;
a plurality of individual modules that each have a plurality of switching elements controlled by the at least one control unit and at least one electrical energy store, wherein the plurality of individual modules are connected together in succession to form a closed ring, each of the plurality of individual modules configurable by the at least one control unit between at least a bypass connection and a series connection with an adjacent module by the plurality of switching elements allowing energy stores of adjacent individual modules to be selectively connected together; and
at least four phase terminals on the dosed ring, each phase terminal connected between respective adjacent individual modules of the dosed ring and separated from an adjacent phase terminal by at least two individual modules of the closed ring, wherein a voltage difference between two adjacent phase terminals of the closed ring is regulated by the at least one control unit configuring the plurality of individual modules.
2. The modular multilevel converter as claimed in claim 1 , in which each of at least four taps are arranged between two respective adjacent individual modules to provide the at least four phase terminals.
3. The modular multilevel converter as claimed in claim 1 , in which the modular multilevel converter has a phase module comprising at least two individual modules that branches off from the ring and that has one end connected to a tap and has the other end connected to a reference potential.
4. The modular multilevel converter as claimed in claim 1 , in which at least one tap is connected to a reference potential via an electrical connection that has at least one electrical resistance, an inductance or both at least one electrical resistance and an inductance.
5. The modular multilevel converter as claimed in claim 1 , in which the switching elements of the multiplicity of individual modules are low-voltage semiconductor switching elements.
6. An electrical polyphase system comprising:
an electric machine that has a multiplicity of windings having a first terminal and a second terminal,
at least one node to which either the first or the second terminal of a respective winding from the multiplicity of windings is electrically connected, and the corresponding other terminal of the first and second terminals of a respective winding from the multiplicity of windings is electrically connected to a phase terminal, and
the modular multilevel converter of claim 1 , wherein at least one tap is arranged between two respective adjacent individual modules of the plurality of modules and provides a phase terminal to which the first or the second terminal of a winding from the multiplicity of windings of the electric machine is electrically connected,
wherein a number of taps of the modular multilevel converter corresponds exactly to a number of windings from the multiplicity of windings of the electric machine.
7. The electrical polyphase system as claimed in claim 6 , in which the electric machine operates as a generator or as a motor.
8. The converter of claim 1 , wherein the individual modules are additionally configurable by the control unit in at least one of a disconnection or a parallel connection with the adjacent module by the plurality of switching elements.
9. The modular multilevel converter as claimed in claim 2 , in which each of the individual modules have a first side and a second side, the first side having two terminals and the second side having two terminals.
10. The modular multilevel converter as claimed in claim 9 , in which the individual modules are each electrically connected to one another by two electrical conductors.
11. The modular multilevel converter as claimed in claim 10 , in which the tap for providing a phase terminal is arranged on one of the two electrical conductors.
12. The modular multilevel converter as claimed in claim 10 , in which the tap for providing a phase terminal is arranged on both electrical conductors.