NOVEL MULTI-LEVEL CONVERTER TOPOLOGY WITH THE POSSIBILITY OF DYNAMICALLY CONNECTING INDIVIDUAL MODULES IN SERIES AND IN PARALLEL

• US 20140049230A1
• Filed: 10/25/2011
• Published: 02/20/2014
• Est. Priority Date: 11/30/2010
• Status: Active Grant

• Current Assignee: Technische Universitat Munchen
• Original Assignee: Technische Universitat Munchen
• Inventors: Weyh, Thomas
• Granted Patent: US 9,502,960 B2
• Time in Patent Office: Days
• US Class Current: 323/207
• CPC Class Codes: H02M 1/42 Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
• CPC Class Codes: H02M 7/483 Converters with outputs that each can have more than two voltages levels
• 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

Abstract

The present invention describes an electrical converter system for power supply systems, comprising at least two identical individual modules connected consecutively, characterised in that each individual module have at least four internal switching elements, at least one energy storage element and at least four connectors, wherein the connectors are paired and serve as a first and a second terminal pair; the internal switching elements of each individual module are designed in such manner that they are able to selectively connect one or both connectors of each terminal pair to the energy storage element; the cascaded connection of at least two individual modules is made in such manner that the connectors in the second terminal pair of a preceding individual module are each connected to the connectors of the first terminal pair in the respective following individual module, and at least one terminal of the first terminal pair of the first individual module of the cascaded connection and at least one terminal of the second terminal pair of the last individual module of the cascaded connection serve as terminals for the cascaded connection; and wherein the switching elements of the respective individual modules in the cascaded connection of at least two individual modules connect their respective energy storage element to the terminals of the cascaded connection in such manner that a selective serial or parallel connection of the energy storage elements is made.

Claims

1-22. -22. (canceled)

23. An electrical converter system for power supplies, comprising at least two identical individual modules in a cascade connection, characterised in that

each individual module has at least three, preferably at least four internal switching elements, at least one energy storage element and at least four connectors, wherein the connectors serve in pairs as a first and a second terminal pair;

and

at least two individual modules are cascade connected in such manner that each of the connectors of the second terminal pair of a preceding individual module is connected with

either the connectors of the first terminal pair of the respective following individual module, or

connectors of at least one intermediate module, which is arranged between the preceding individual module and the respective following individual module,

wherein the switching elements of the respective individual modules in the cascade connection of the at least two individual modules connect their respective energy storage elements to the terminals of the cascade connection thereof in such manner that a selectively series or parallel connection of the energy storage elements is made.

24. The electrical converter system according to claim 23, in which at least one terminal of the first terminal pair of the first individual module of the cascade connection and at least one terminal of the second terminal pair of the last individual module of the cascade connection serve as terminals of the cascade connection.

25. The electrical converter system according to claim 23, in which the internal switching elements of each individual module are designed in such manner that they can selectively connect one or both connectors of a terminal pair to the energy storage element.

26. The electrical converter system according to claim 23, in which the individual modules are each designed in such manner that a connector of the first terminal pair is connected internally with a connector of the second terminal pair.

27. The electrical converter system according to claim 23, wherein the switching elements are in the form of bipolar transistors, IGBTs, MOSFETs, thyristors or GTOs.

28. The electrical converter system according to claim 23, wherein a diode is additionally arranged parallel to at least some of the switching elements, preferably parallel to each switching element, and the diodes are connected in such manner that they protect the switching elements from polarity reversal and overload.

29. The electrical converter system according to claim 28, in which the diodes are connected in such manner that when all switching elements are open energy can only flow into said energy storage element.

30. The electrical converter system according to claim 23, wherein the converter system operates according to the pulse width modulation principle and the current strength is altered via the duty cycle of the pulse width modulation.

31. The electrical converter system according to claim 23, wherein the energy storage element is designed as a capacitor, an accumulator or a solar cell.

32. The electrical converter system according to claim 23, wherein the switching elements of an individual module of a cascade connection can also be controlled in such manner that no current can flow through the energy storage element or that no electrical connection with a following individual module is present.

33. The electrical converter system according to claim 23, wherein the cascade connection of individual modules also contains additional modules with other properties.

34. The electrical converter system according to claim 23, in which the at least one intermediate module has the form of a balancing member for intermediate buffering of energy from the energy storage element, wherein said balancing member preferably has an inductance.

35. The electrical converter system according to claim 23, wherein the cascade connection of the individual modules forms a bridge branch of a converter.

36. The electrical converter system according to claim 35, in which the terminals of the first terminal pair of the first individual module of the cascade connection are connected to one another and form a first terminal of the bridge branch, and the terminals of the second terminal pair of the last individual module of the cascade connection are connected to one another and form a second terminal of the bridge branch.

37. The electrical converter system according to claim 35, wherein the individual modules of a bridge branch that are in the middle are designed with a lower current carrying capacity than the individual modules that are arranged closer to the ends of the bridge branch.

38. The electrical converter system according to claim 35, wherein the bridge branch formed by a pulse width modulated actuation of the individual modules offsets the phase of the current of an AC voltage source relative to the voltage thereof in such manner that the bridge branch can be used for power factor correction.

39. The electrical converter system according to claim 35, wherein bridge branches are connected in pairs to form a phase module and a plurality of such phase modules are connected together to form a common busbar in order to connect the input and/or output side of the converter to a multiphase system.

40. The electrical converter system according to claim 23, in which the individual module can be derived from one of a first, a second and a third module type,

wherein the first module time comprises the following:

a first and a second conductor,

an energy storage element C_S, connected between the first and the second conductor,

four bridge branches, connected between the first and the second conductor,

wherein each bridge branch comprises a pickup that may be connected to the first conductor via a first switching element and to the second conductor via a second switching element, and

wherein each of the at least four connections of the individual module is connected to one of the pickups on the four bridge branches;

wherein a module of the second module type comprises the following;

a first and a second conductor,

an energy storage element, connected between the first and the second conductor,

two bridge branches connected between the first and the second conductor, wherein

each bridge branch comprises a first pickup that may be connected to the first conductor via a first switching element a second pickup that may be connected to the second conductor via a second switching element, and the first and second pickups may be connected to one another via a third switching element, and

wherein one terminal of the first terminal pair is connected to the first or second pickup of one bridge branch, and one terminal of the second terminal pair is connected to the first or second pickup of the other bridge branch, and

wherein a module of the third module type comprises the following;

a first and a second conductor,

an energy storage element, connected between the first and the second conductor,

a bridge branch connected between the first and the second conductor,

wherein the bridge branch comprises a pickup that may be connected to the first conductor via a first switching element and to the second conductor via a second switching element,

wherein the one terminal of the first terminal pair is connected to the pickup and the other terminal of the first terminal pair may be connected to the first conductor via a third switching element,

wherein a terminal of the second terminal pair may be connected to the first conductor via a fourth switching element, and

wherein the other terminal of the second terminal pair is connected to the second conductor,

and wherein an individual module is derived from a module type by the removal of individual switching elements of the module of the respective type or replacement thereof with conductors in such manner that it is still possible with the remaining switching elements for the energy storage element to be connected selectively in series or in parallel with an energy storage element of an adjacent module.

41. A method for actuating a converter for control of currents and voltages, wherein the converter comprises consecutively connected individual modules and wherein each individual module has at least three, preferably at least four internal switching elements, at least one energy storage element and at least four connectors, wherein pairs of the connectors serve as a first and a second terminal pair, wherein the method comprises the following steps:

connecting the energy storage elements of consecutive individual modules via the internal switching elements in such manner that a selectively series or parallel connection of these energy storage elements is created,

wherein the cascade connection of at least two individual modules is designed in such manner that the connectors of the second terminal pair of a preceding individual module are is connected

either with the connectors of the first terminal pair of the respective following individual module, or

connectors of at least one intermediate module, which is arranged between the preceding individual module and the respective following individual module.

42. A method according to claim 41, wherein the individual modules are actuated according to the principle of pulse width modulation such that the converter is able to change the current strength via the duty cycle of the pulse width modulation.

43. A method according to claim 42, wherein the individual modules of the converter are actuated in such manner that a phase offset is created between the current and voltage of a generated AC voltage, such that the converter can be used for power factor correction at the input and or output.

44. The method according to claim 41, in which one or both connectors of any terminal pair are connected selectively to the energy storage element.