Wind turbine power conversion system

Patent metadata

Field	Value
Publication number	US-2016146192-A1
Application number	US-201414555336-A
Country	US
Kind code	A1
Filing date	Nov 26, 2014
Priority date	Nov 26, 2014
Publication date	May 26, 2016
Grant date	—

Abstract

The invention refers to a multilevel topology power converter (I) for electrical adaption of a low voltage alternating current (LVAC) of an electrical wind power generator ( 1 ) and a medium voltage (MV) transmission level for a transmission link to each other, the power converter (I) comprising for each phase:
a switching unit ( 9 ) for adapting the low voltage (LV) and the medium voltage (MV) to each other, the switching unit ( 9 ) being controlled by a controller ( 15 ), whereby the controlled switching unit ( 9 ) separately switches n+1 terminal potentials along terminals of an electrical series of n>1 capacitors C 1 . . . Cn ( 7 ); a current converter ( 5 ) for providing or using a direct current (DC) through the plurality of n>1 capacitors C 1 . . . Cn ( 7 ) connected in series.

First claim

1 . Multilevel topology power converter (I) for electrical adaption of a low voltage alternating current (LVAC) of an electrical wind power generator ( 1 ) and a medium voltage (MV) transmission level for a transmission link to each other, the power converter (I) comprising for each phase:
a switching unit ( 9 ) for adapting the low voltage (LV) and the medium voltage (MV) to each other, the switching unit ( 9 ) being controlled by a controller ( 15 ).

2 . Multilevel topology power converter (I) according to claim 1 characterized by
comprising for each phase a current converter ( 5 ) for providing a direct current (DC) towards or from a plurality of n>1 capacitors C 1 . . . Cn ( 7 ) electrically connected in series, whereby the controlled switching unit ( 9 ) switches n+1 terminal potentials along terminals of the series of the n>1 capacitors C 1 . . . Cn ( 7 ).

3 . Multilevel topology power converter (I) according to claim 2 characterized by comprising for each phase:
the current converter ( 5 ) for providing at two main terminals a low voltage direct current (LVDC) from or to the low voltage alternating current (LVAC) of the electrical power generator ( 1 );
the plurality of n>1 capacitors C 1 . . . Cn ( 7 ) electrically connected in series between the two main terminals of the low voltage direct current (LVDC);
the controlled switching unit ( 9 ) for separately switching n+1 terminal potentials along terminals of the series of the n>1 capacitors C 1 . . . Cn ( 7 ) to provide a medium voltage alternating current (MVAC) for or from the transmission link.

4 . Multilevel topology power converter (I) according to claim 2 characterized by comprising for each phase:
the electrical power generator ( 1 ) generating or adjusting to the low voltage alternating current (LVAC);
the controlled switching unit ( 9 ) for separately switching n+1 terminal potentials from or to the electrical generator ( 1 ) along terminals of the series of n>1 capacitors C 1 . . . Cn ( 7 ) electrically connected in series between two main terminals to provide a first medium voltage direct current (MVDC) at the two main terminals;
the current converter ( 5 ) for adapting the first medium voltage direct current (MVDC) and a second medium voltage direct current (MVDC) for the transmission link to each other.

5 . Multilevel topology power converter (I) claim 1 , characterized in that
the controlled switching unit ( 9 ) comprises semiconductor, in particular IGBT devices AC line voltages in particular medium voltages i.e., 10 kV or higher.

6 . Multilevel topology power converter (I) according to claim 4 , characterized in that
a plurality of electrical power generator ( 1 ) assembly levels (L 1 . . . Li) is electrically connected in parallel to each other and their current converters ( 5 ) adapt their second medium voltage direct currents (MVDC) to each other.

7 . Multilevel topology power converter (I) according to claim 6 , characterized in that
the plurality of electrical power generator ( 1 ) assembly levels (L 1 . . . Li) is electrically connected in parallel to a common current converter ( 11 ) which adapts the voltage of the second medium voltage direct current (MVDC) with a higher voltage of the second medium voltage direct current (MVDC) for the transmission link.

8 . Multilevel topology power converter (I) according to claim 7 , characterized in that
a DC/AC converter ( 13 ) adapts the higher voltage of the second medium voltage direct current (MVDC) with a high voltage alternating current (HVAC).

9 . Multilevel topology power converter (I) according to claim 3 , characterized in that
an AC/AC converter ( 17 ) adapts the medium voltage alternating current (MVAC) with a high voltage alternating current (HVAC).

10 . Multilevel topology power converter (I) according to claim 1 , characterized in that
the controller ( 15 ) of the converter (I) controls in a dual mode operating by load angle (Θ) control in a stand-alone mode (M 1 ) and by current control in a grid-connected mode (M 2 ) of the electrical wind power generator ( 1 ).

11 . Multilevel topology power converter (I) according to claim 10 , characterized in that
the controller ( 15 ) of the converter (I) switches from the standard current control of the grid-connected mode to the load angle (Θ) control of the stand-alone mode of the electrical wind power generator ( 1 ) and vice versa.

12 . Multilevel topology power converter (I) according to claim 10 , characterized in that
the controller ( 15 ) of the converter (I) generates an own reference signal while operating in the stand-alone mode.

13 . Multilevel topology power converter (I) according to claim 10 , characterized in that
in the stand-alone mode the controller ( 15 ) of the converter (I) controls the active power (P) output of the converter (I) by the load angle (Θ) control, if the converter (I) regulates to a constant output voltage (VPCC) of the converter (I).

14 . Multilevel topology power converter (I) according to claim 13 , characterized in that
in the stand-alone mode the controller ( 15 ) of the converter (I) regulates to the constant output voltage (VPCC) thus the active power (P) output of the converter (I) is proportional to the load angle (Θ).

15 . Multilevel topology power converter (I) according to claim 10 , characterized in that for the stand-alone mode within the converter (I) the capacities of the capacitors C 1 . . . Cn are increased to provide a stiffer series of the capacitors C 1 . . . Cn.

16 . Multilevel topology power converter (I) according to claim 10 , characterized in that for the stand-alone mode the converter (I) comprises a voltage regulation of the voltages at the capacitors C 1 . . . Cn.

17 . Method for controlling a multilevel topology power converter (I) for electrical adaption of a low voltage alternating current (LVAC) of an electrical wind power generator ( 1 ) and a medium voltage (MV) transmission level for a transmission link to each other, the power converter (I) comprising for each phase:
a switching unit ( 9 ) for adapting the low voltage (LV) and the medium voltage (MV) to each other, the switching unit ( 9 ) being controlled by a controller ( 15 ), and a current converter ( 5 ) for providing a direct current (DC) towards or from a plurality of n>1 capacitors C 1 . . . Cn ( 7 ) electrically connected in series, whereby the controlled switching unit ( 9 ) switches n+1 terminal potentials along terminals of the series of the n>1 capacitors C 1 . . . Cn ( 7 ), characterized in that the controller ( 15 ) of the converter (I) controls in a dual mode operating by load angle (Θ) control in a stand-alone mode and by current control in a grid-connected mode of the electrical wind power generator ( 1 ).

18 . Method for controlling a multilevel topology power converter (I) according to claim 17 , characterized in that
the controller ( 15 ) of the converter (I) controls in a dual mode operating by load angle (Θ) control in a stand-alone mode and by current control in a grid-connected mode of the electrical wind power generator ( 1 ).

19 . Method for controlling a multilevel topology power converter (I) according to claim 17 , characterized in that
the controller ( 15 ) of the converter (I) switches from the standard current control of the grid-connected mode to the load angle (Θ) control of the stand-alone mode of the electrical wind power generator ( 1 ) and vice versa.

20 . Method for controlling a multilevel topology powe

Assignees

• Siemens Ag

Inventors

• Kurthakoti Chandrashekhara Divya
• Hergt Martin
• Schacherer Christian

Classifications

• F03D9/003 Primary

  Mechanical Engineering · mapped topic

• H02M5/44

  using discharge tubes or semiconductor devices to convert the intermediate DC into AC · CPC title

• F03D9/255 Primary

  connected to electrical distribution networks; Arrangements therefor · CPC title

• H02M1/007

  Plural converter units in cascade (push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826) · CPC title

• Y02E10/76

  Power conversion electric or electronic aspects · CPC title