CONVERTER, ELECTRICAL POLYPHASE SYSTEM AND METHOD

• US 20170163115A1
• Filed: 12/05/2016
• Published: 06/08/2017
• Est. Priority Date: 12/07/2015
• Status: Active Grant

• Current Assignee: Dr Ing hc F Porsche AG (Volkswagen AG)
• Original Assignee: Dr Ing hc F Porsche AG (Volkswagen AG)
• Inventors: Gtz, Stefan
• Granted Patent: US 10,454,331 B2
• Time in Patent Office: Days
• CPC Class Codes: H02K 11/33 Drive circuits, e.g. power electronics H02K11/38 takes precedence
• CPC Class Codes: H02K 17/12 for multi-phase current
• CPC Class Codes: H02K 2213/12 Machines characterised by the modularity of some components
• CPC Class Codes: H02K 3/28 Layout of windings or of connections between windings windings for pole-changing H02K17/06, H02K17/14, H02K19/12, H02K19/32
• CPC Class Codes: H02M 7/4835 comprising two or more cells, each including a switchable capacitor, the capacitors having a nominal charge voltage which corresponds to a given fraction of the input voltage, and the capacitors being selectively connected in series to determine the instantaneous output voltage
• CPC Class Codes: H02M 7/49 Combination of the output voltage waveforms of a plurality of converters
• CPC Class Codes: H02P 25/22 Multiple windings; Windings for more than three phases
• CPC Class Codes: H02P 27/06 using dc to ac converters or inverters H02P27/05 takes precedence
• CPC Class Codes: H02P 27/14 with three or more levels of voltage

Abstract

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.

Claims

1. A modular multilevel converter having a plurality of individual modules that each have a plurality of switching elements and at least one electrical energy store, wherein the individual modules are connected together in succession to form a closed ring, with the plurality of switching elements allowing energy stores of adjacent individual modules to be connected together, as a result of which a voltage difference that is regulable by a control unit in accordance with a profile of a polyphase rotating field can be provided between two adjacent phase terminals or two adjacent windings of the closed ring.

2. The modular multilevel converter as claimed in claim 1, in which at least one tap is arranged between two respective adjacent individual modules and provides a phase terminal, and at least two individual modules that form a phase module are arranged between two adjacent taps.

3. 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.

4. The modular multilevel converter as claimed in claim 3, in which the individual modules are each electrically connected to one another by two electrical conductors.

5. The modular multilevel converter as claimed in claim 4, in which the tap for providing a phase terminal is arranged on one of the two electrical conductors.

6. The modular multilevel converter as claimed in claim 4, in which the tap for providing a phase terminal is arranged on both electrical conductors.

7. 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.

8. 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.

9. The modular multilevel converter as claimed in claim 8, in which multiple taps are connected to the reference potential via one electrical connection each that has at least one electrical resistance, an inductance or both at least one electrical resistance and an inductance, the multiple taps dividing the ring of the individual modules symmetrically.

10. 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.

11. 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

a modular multilevel converter that has a multiplicity of individual modules that are connected together in series to form a ring, wherein at least one tap is 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,

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, and

wherein the individual modules of the modular multilevel converter each have an energy store and a plurality of switching elements that allows energy stores of adjacent individual modules to be connected together, as a result of which a voltage difference that is regulable by a control unit in accordance with a profile of a polyphase rotating field can be provided between two adjacent phase terminals or two adjacent windings.

12. The electrical polyphase system as claimed in claim 11, in which the electric machine operates as a generator or as a motor.

13. A method for operating an electrical polyphase system in which an electric machine and a modular multilevel converter are used, wherein the electric machine has a multiplicity of windings having a first terminal and a second terminal, and either the first terminal or the second terminal of a respective winding from the multiplicity of windings is connected to a node to which each winding from the multiplicity of windings is connected, and the corresponding other terminal of the first and second terminals of a respective winding from the multiplicity of windings is connected to a phase terminal, and wherein the modular multilevel converter has a multiplicity of individual modules that are connected together in series to form a ring, and at least one tap is 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, the individual modules of the modular multilevel converter each having an energy store and a plurality of switching elements that allows energy stores of adjacent individual modules to be connected together, said method comprising:

providing a voltage difference that is regulated by a control unit in accordance with a profile of a polyphase rotating field between two adjacent phase terminals or two adjacent windings.

14. The method as claimed in claim 13, in which at least two individual modules that form a phase module are arranged between two taps.

15. The method as claimed in claim 13, in which the individual modules used are individual modules that have a first side and a second side, the first side having two terminals and the second side having two terminals.

16. The method as claimed in claim 15, in which the individual modules are each electrically connected to one another by two electrical conductors.

17. The method as claimed in claim 16, in which the tap for providing a phase terminal is arranged on one of the two electrical conductors.

18. The method as claimed in claim 16, in which the tap for providing a phase terminal is arranged on both electrical conductors.

19. The method as claimed in claim 13, in which the converter has a phase module arranged on it that branches off from the ring and that has one end connected to the at least one tap and has the other end connected to a reference potential.

20. The method as claimed in claim 13, in which the 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.

21. The method as claimed in claim 19, in which multiple taps are connected to the 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, the multiple taps dividing the ring of the individual modules symmetrically.

22. The method as claimed in claim 13, in which the switching elements used from the multiplicity of individual modules are low-voltage semiconductor switching elements.

23. The method as claimed in claim 13, in which the electric machine operates as a generator or as a motor.