AC/DC voltage transformer and method of operation therefor

Patent metadata

Field	Value
Publication number	US-9729078-B2
Application number	US-201314376685-A
Country	US
Kind code	B2
Filing date	Feb 5, 2013
Priority date	Feb 6, 2012
Publication date	Aug 8, 2017
Grant date	Aug 8, 2017

Abstract

A method for actuating an AC/DC voltage converter is specified, which has a DC voltage output between which at least one series circuit of at least two capacitors and at least one series circuit of n switching elements-is arranged, where n≧4. A connecting point of the switching elements is connected to a connection of an AC voltage input between n/2 switching elements. Two diodes are connected in an antiparallel arrangement to the two switching elements lying closest to the connecting point. In addition, a connecting point of the capacitors is connected to a connecting point of the diodes. An output voltage at the DC voltage output and a potential of the connecting point of the capacitors or diodes are provided as controlled variables, an input current at the AC voltage input is provided as a manipulated variable and the switching elements are provided as an actuating element of a control loop. In addition, a controller for implementing the method and an AC/DC voltage converter containing such a controller are specified.

First claim

The invention claimed is:

1. A method of actuating an AC/DC voltage converter having a DC voltage output between which at least one series circuit of at least two capacitors and at least one series circuit of n switching elements is arranged, where n≧4, and a connecting point of the switching elements between n/2 switching elements is connected to a connection of an AC voltage input, a series circuit of at least two diodes is connected in an antiparallel arrangement to at least the series circuit of the two switching elements lying closest to said connecting point, and a connecting point of the capacitors is connected to a connecting point of the diodes,
wherein
an output voltage at the DC voltage output and a potential of said connecting point of the capacitors or diodes are provided as controlled variables,
an input current at the AC voltage input is provided as a manipulated variable,
the switching elements are provided as an actuating element of a control loop and
at least two switching elements are connected to each other serially, lie on one side of said connecting point of the switching elements, form an AND gate, and are actuated differently so that the resultant switch signal is the result of the AND collated individual signals,
wherein at least one of the switching elements lying on one side of said connecting point is actuated by a clock signal having the same frequency as an input voltage of the AC voltage input,
wherein at least one of the switching elements lying on the other side of said connecting point is actuated by an inverse signal to said clock signal, and
wherein on both sides of the connection point at least one of the switching elements which is not actuated by the clock signal or the inverse signal thereto is actuated by a pulse width modulated signal.

2. The method according to claim 1 , wherein the shape of the input current is preset.

3. The method according to claim 2 , wherein the output voltage at the DC voltage output is controlled with the aid of an amplitude of the input current.

4. The method according to claim 3 , wherein the potential of said connecting point of the capacitors or diodes is controlled with the aid of the amplitude of the input current.

5. The method according to claim 3 , wherein the potential of said connecting point of the capacitors or diodes is controlled with the aid of a pulse which is superimposed on the input current and selectively actuates the switching elements.

6. The method according to claim 1 , wherein a phase shift between an input current and an input voltage is preset.

7. A controller for an AC/DC voltage converter having a DC voltage output between which at least one series circuit of at least two capacitors and at least one series circuit of n switching elements is arranged, where n≧4, and a connecting point of the switching elements between n/2 switching elements is connected to a connection of an AC voltage input, and a series circuit of at least two diodes is connected in an antiparallel arrangement to at least the series circuit of the two switching elements lying closest to said connecting point, and a connecting point of the capacitors is connected to a connecting point of the diodes,
comprising
an input for the output voltage at the DC voltage output and a potential of said connecting point of the capacitors or diodes,
outputs for actuating the switching elements and
a control device configured to run a control algorithm, whereby the output voltage and said potential are provided as controlled variables, an input current at the AC voltage input is provided as a manipulated variable and the switching elements are provided as an actuating element of a control loop and wherein at least two switching elements are connected to each other serially, lie on one side of said connecting point of the switching elements, form an AND gate, and are actuated differently so that the resultant switch signal is the result of the AND collated individual signals,
wherein at least one of the switching elements lying on one side of said connecting point is actuated by a clock signal having the same frequency as an input voltage of the AC voltage input,
wherein at least one of the switching elements lying on the other side of said connecting point is actuated by an inverse signal to said clock signal, and
wherein on both sides of the connection point at least one of the switching elements which is not actuated by the clock signal or the inverse signal thereto is actuated by a pulse width modulated signal.

8. An AC/DC voltage converter having a DC voltage output between which at least one series circuit of at least two capacitors and at least one series circuit of n switching elements is arranged, where n≧4, and a connecting point of the switching elements between n/2 switching elements is connected to a connection of an AC voltage input, and a series circuit of at least two diodes is connected in an antiparallel arrangement to at least the series circuit of the two switching elements lying closest to said connecting point, and a connecting point of the capacitors is connected to a connecting point of the diodes,
comprising
the controller according to claim 7 ,
the input of which for output voltage at the DC voltage output is connected to precisely this DC voltage output,
the input of which for the potential of said connecting point of the capacitors or diodes is connected precisely to this connecting point and
outputs of which for actuating the switching elements are connected to precisely these switching elements.

9. The AC/DC voltage converter according to claim 8 , wherein the connecting point of the capacitors or diodes is connected to a neutral terminal of the AC voltage input.

10. The AC/DC voltage converter according to claim 8 , wherein the connecting point of the switching elements is connected to a phase connection of the AC voltage input.

11. The AC/DC voltage converter according to claim 8 , wherein the switching elements are provided in the form of MOSFETs having body diodes and wherein the at least two diodes are the body diodes.

Assignees

• Fronius Int Gmbh

Inventors

• Achleitner Guenter
• Trauner Gernot
• Pamer Andreas

Classifications

• H02M7/487

  Neutral point clamped inverters · CPC title

• H02M7/10 Primary

  arranged for operation in series, e.g. for multiplication of voltage · CPC title

• H02M7/219 Primary

  in a bridge configuration · CPC title

• H02M1/14

  Arrangements for reducing ripples from DC input or output · CPC title

• H02M7/217

  using semiconductor devices only · CPC title