1. A power system for providing an output power to a load, the system comprising;
a generator configured to generate an alternating current input power to a power converter system;
a power converter system coupled to the generator and interconnected to generate an output power and provide the output power to the load, wherein the converter system includes a plurality of parallel converter threads;
a converter control system coupled to the power converter system and configured to drive the converter system to reduce harmonic components in the output power or the alternating current input power; and
isolation means for the output power from the converter to the load, adapted to prevent common mode current circulation between the parallel converter threads.
2. The power system of claim 1, the power converter system further comprising:
isolation means for the output power including a plurality of sets of isolated power windings on the output transformer from the converter wherein each set of the plurality of sets of isolated power windings of the output transformer connects with one of a corresponding parallel converter thread of the plurality of parallel converter threads.
3. The power system of claim 2 wherein the set of isolated power windings on the output transformer comprises a three-phase power winding and each of the plurality of parallel converter threads comprises a three-phase power input.
4. The power system of claim 3, wherein the three-phase power winding comprises:
wye-connected power input windings.
5. The power system of claim 3 wherein the three-phase power winding comprises:
delta-connected generator power input windings.
6. The power system of claim 3, wherein the three-phase power winding comprises:
at least one of delta-wye configured power windings and wye-delta power windings.
7. The power system of claim 3, wherein the generator comprises: a wind turbine generator.
8. The power system of claim 3 wherein the load comprises: an electric power grid.
9. The power system of claim 3, wherein the converter control system drives the parallel converter threads of the converter system according to an interleaved control scheme.
10. The power system of claim 3, wherein the converter control system drives the parallel converter threads of the converter system according to a non-interleaved control scheme.
11. A method for eliminating common mode currents in a power system supplying a power output to a load from a power converter system including a plurality of parallel converter threads, the method comprising:
operating the generator according to a controller to supply ac power to a power converter system;
operating the plurality of converter threads to supply power to a load according to a controller for the power converter system adapted to drive the power converter system to reduce harmonic components in the power output or the alternating current input power; and
supplying the ac power from the power system converter to a load through a plurality of sets of isolated power windings of a transformer on the load side of the power system converter, wherein each converter thread of the plurality of converter threads feeds corresponding isolated power transformer windings.
12. The method for eliminating common mode currents according to claim 11, comprising: supplying the ac power to the load from the power system converter through sets of isolated three-phase power windings on the transformer.
13. The method for eliminating common mode currents according to claim 12, further comprising: supplying the ac power to the load from the power system converter through sets of isolated, wye-configured, three-phase power windings on the transformer.
14. The method for eliminating common mode currents according to claim 12, further comprising: supplying the ac power to the load from the power system converter through sets of isolated, delta-configured, three-phase power windings on the transformer.
15. The method for eliminating common mode currents according to claim 12, further comprising: supplying the ac power to the load from the power system converter through at least sets of isolated, wye-delta, three-phase power windings on the transformer and sets of isolated, delta-wye, three-phase power windings on the transformer.
16. The method for eliminating common mode currents according to claim 12, wherein the generator comprises a wind turbine generator and the load comprises an electric power grid.
17. The method for eliminating common mode currents according to claim 12 further comprising: driving the parallel converter threads of the converter system by the converter control system according to an interleaved control scheme.
18. The method for eliminating common mode currents according to claim 12 further comprising: driving the parallel converter threads of the converter system by the converter control system according to a non-interleaved control scheme.
19. A wind turbine power system adapted to prevent common mode current circulation among power system converter threads when providing output power to an electrical power grid, the system comprising;
a wind turbine generator controlled by a wind turbine controller configured to generate an alternating current input power to a power converter system;
a power converter system coupled to the wind turbine generator and interconnected to generate an output power and provide the output power to the load, wherein the power converter system includes a plurality of the parallel converter threads;
a converter control system coupled to the power converter system and configured to drive the parallel converter threads to reduce harmonic components in the output power or the alternating current input power; and
a plurality of sets of isolated power windings on a power transformer on the output side of the converter, wherein each set of the plurality of sets of isolated power windings of the generator interconnects with only one of a corresponding parallel converter thread of the plurality of parallel converter threads.
20. The wind turbine power system according to claim 19, wherein the sets of isolated power windings on the wind turbine generator comprise: three-phase power winding configured in at least one of a wye configuration, a delta configuration, a delta-wye configuration and a wye-delta configuration.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A motion estimation method adaptive to change in illumination, comprising the steps of:
(a) generating a current frame pattern block for a current frame block and a reference frame pattern block for a reference frame block;
(b) calculating the sum of absolute differences (SAD) for candidate pattern blocks corresponding to the current frame pattern block among the reference frame pattern blocks and determining the candidate pattern block corresponding to the SAD satisfying a predetermined condition among the calculated SADs as a motion vector;
(c) encoding the current frame block, by generating a residual signal using a difference signal between the candidate pattern block corresponding to the motion vector and the current frame pattern block then performing discrete cosine transform and quantization to the residual signal with a predetermined encoding mode; and
(d) adding flag information indicating the addition of a mean pixel value applied to the encoded current frame block and identification information on the encoding mode as header information corresponding to the encoded current frame block;
wherein the addition of a mean pixel value to be applied to the current frame block is identified by the flag information.
2. The motion estimation method according to claim 1, wherein step (a) includes the steps of:
calculating a mean brightness value of the current frame block and a mean brightness value of the reference frame block; and
generating the current frame pattern block by subtracting the mean brightness value of the current frame block from brightness values of the current frame block and generating the reference frame pattern blocks by subtracting the mean brightness value of the reference frame block from brightness values of the reference frame block.
3. The motion estimation method according to claim 1, further comprising encoding the mean pixel value of the current frame block.
4. The motion estimation method according to claim 1, wherein the SAD satisfying the predetermined condition indicates the least SAD and the SAD is calculated by the following equation:
NewSAD
\u2061
(
x
,
y
)
=
\u2211
i
=
0
U
–
1
\u2062
\u2211
j
=
0
V
–
1
\u2062
\uf603
f
\u2061
(
i
,
j
)
–
M
curr
–
r
\u2061
(
i
+
x
,
j
+
y
)
–
M
ref
\uf604
where Mcurr denotes the mean pixel value of the current frame block, Mref denotes the mean pixel value of the candidate pattern blocks, f(i,j) denotes a pixel value at a coordinate (i,j) of the current frame, r(i,j) denotes a pixel value of a coordinate (i,j) of the reference frame, U and V denote the sizes of blocks used for matching the blocks, and (x,y) denotes the motion vector.
5. The motion estimation method, according to claim 1, wherein the residual signal is calculated by the following equation:
NewR
\u2061
(
i
,
j
)
=
f
\u2061
(
i
,
j
)
–
M
curr
–
r
\u2061
(
i
+
MV
x
,
j
+
MV
y
)
–
M
ref
=
f
\u2061
(
i
,
j
)
–
r
\u2061
(
i
+
MV
x
,
j
+
MV
y
)
–
M
curr
+
M
ref
\u2003
where NewR denotes the residual signal, Mcurr denotes the mean pixel value of the current frame block, Mref denotes the mean pixel value of the candidate pattern blocks, f(i,j) denotes a pixel value at a coordinate (i,j) of the current frame, r(i,j) denotes a pixel value of a coordinate (i,j) of the reference frame, U and V denote the sizes of blocks used for matching the blocks, and (x,y) denotes the motion vector.
6. A motion estimation device comprising:
a pattern block generating unit generating a current frame pattern block of a current frame block and reference frame pattern blocks of a reference frame block;
a motion vector determining unit calculating the sum of absolute differences (SAD) of candidate pattern blocks corresponding to the current frame pattern block among the reference frame pattern blocks and determining the candidate pattern block corresponding to the SAD satisfying a predetermined condition among the calculated SADs as a motion vector;
a motion compensation unit generating a residual signal using a difference signal between the candidate pattern block corresponding to the motion vector and the current frame pattern block; and
an adding unit adding flag information indicating the addition of a mean pixel value applied to the encoded current frame block and identification information on the encoding mode as header information corresponding to the encoded current frame block;
wherein the addition of a mean pixel value to be applied to the current frame block is identified by the flag information.
7. The motion estimation device according to claim 6, wherein the pattern block generating unit:
calculates a mean brightness value of the current frame block and a mean brightness value of the reference frame block;
generates the current frame pattern block by subtracting the mean brightness value of the current frame block from brightness values of the current frame block; and
generates the reference frame pattern blocks by subtracting the mean brightness value of the reference frame block from brightness values of the reference frame block.
8. The motion estimation device according to claim 6, further comprising a unit carrying out discrete cosine transform and quantization to the residual signal.
9. The motion estimation device according to claim 6, wherein the SAD satisfying the predetermined condition indicates the least SAD and the motion vector determining unit calculates the SAD with the following equation:
NewSAD
\u2061
(
x
,
y
)
=
\u2211
i
=
0
U
–
1
\u2062
\u2211
j
=
0
V
–
1
\u2062
\uf603
f
\u2061
(
i
,
j
)
–
M
curr
–
r
\u2061
(
i
+
x
,
j
+
y
)
–
M
ref
\uf604
where Mcurr denotes the mean pixel value of the current frame block, Mref denotes the mean pixel value of the candidate pattern blocks, f(i,j) denotes a pixel value at a coordinate (i,j) of the current frame, r(i,j) denotes a pixel value of a coordinate (i,j) of the reference frame, U and V denote the sizes of blocks used for matching the blocks, and (x,y) denotes the motion vector.
10. The motion estimation device according to claim 6, wherein the motion compensation unit calculates the residual signal with the following equation:
NewR
\u2061
(
i
,
j
)
=
f
\u2061
(
i
,
j
)
–
M
curr
–
r
\u2061
(
i
+
MV
x
,
j
+
MV
y
)
–
M
ref
=
f
\u2061
(
i
,
j
)
–
r
\u2061
(
i
+
MV
x
,
j
+
MV
y
)
–
M
curr
+
M
ref
\u2003
where NewR denotes the residual signal, Mcurr denotes the mean pixel value of the current frame block, Mref denotes the mean pixel value of the candidate pattern blocks, f(i,j) denotes a pixel value at a coordinate (i,j) of the current frame, r(i,j) denotes a pixel value of a coordinate (i,j) of the reference frame, U and Y denote the sizes of blocks used for matching the blocks, and (x,y) denotes the motion vector.
11. A motion estimation method comprising the steps of:
(a) generating a current frame pattern block for a current frame block and a reference frame pattern block for a reference frame block;
(b) calculating the sum of absolute differences (SADs) for candidate pattern blocks corresponding to the current frame pattern block among the reference frame pattern blocks and determining the candidate pattern block corresponding to the SAD satisfying a predetermined condition among the calculated SADs as a motion vector;
(c) encoding the current frame block, by generating a residual signal using a difference signal between the candidate pattern block corresponding to the motion vector and the current frame pattern block then performing discrete cosine transform and quantization to the residual signal with a predetermined encoding mode; and
(d) adding flag information indicating whether a mean pixel value of the encoded current frame block is included and identification information on the encoding mode to the encoded current frame block as header information,
wherein whether the mean pixel value of the current frame block is included is identified by the flag information.
12. The motion estimation method according to claim 11, wherein the current frame block is set to at least one type of 16\xd716, 16\xd78, 8\xd716, 8\xd78, 8\xd74, 4\xd78, and 4\xd74.
13. The motion estimation method according to claim 11, wherein when the flag information indicates that the mean pixel value is not included, a mean value of mean pixel values corresponding to n blocks surrounding the current frame block is used as the mean pixel value of the current frame block.
14. The motion estimation method according to claim 11, wherein when the flag information does not contain the mean pixel value and the header information further contains additional information indicating that the mean pixel value corresponding to any block among the blocks surrounding the current frame block should be used, a mean pixel value of the block corresponding to the additional information is used as the mean pixel value of the current frame block.
15. The motion estimation method according to claim 11, wherein step (a) includes the steps of:
calculating a mean brightness value of the current frame block and a mean brightness value of the reference frame block; and
generating the current frame pattern block by subtracting the mean brightness value of the current frame block from brightness values of the current frame block and generating the reference frame pattern blocks by subtracting the mean brightness value of the reference frame block from brightness values of the reference frame block.
16. The motion estimation method according to claim 11, further comprising the step of encoding the mean pixel value of the current frame block.
17. The motion estimation method according to claim 11, wherein the SAD satisfying the predetermined condition indicates the least SAD and the SAD is calculated by the following equation:
NewSAD
\u2061
(
x
,
y
)
=
\u2211
i
=
0
U
–
1
\u2062
\u2211
j
=
0
V
–
1
\u2062
\uf603
f
\u2061
(
i
,
j
)
–
M
curr
–
r
\u2061
(
i
+
x
,
j
+
y
)
–
M
ref
\uf604
where Mcurr denotes the mean pixel value of the current frame block, Mref denotes the mean pixel value of the candidate pattern blocks, f(i,j) denotes a pixel value at a coordinate (i,j) of the current frame, r(i+x,j+y) denotes a pixel value of a coordinate (i+x,j+y) of the reference frame, U and V denote the sizes of blocks used for matching the blocks, and (x,y) denotes the motion vector.
18. The motion estimation method according to claim 11, wherein the residual signal is calculated by the following equation:
NewR
\u2061
(
i
,
j
)
=
f
\u2061
(
i
,
j
)
–
M
curr
–
r
\u2061
(
i
+
MV
x
,
j
+
MV
y
)
–
M
ref
=
f
\u2061
(
i
,
j
)
–
r
\u2061
(
i
+
MV
x
,
j
+
MV
y
)
–
M
curr
+
M
ref
\u2003
where NewR denotes the residual signal, Mcurr denotes the mean pixel value of the current frame block, Mref denotes the mean pixel value of the candidate pattern blocks, f(i,j) denotes a pixel value at a coordinate (i,j) of the current frame, r(i,j) denotes a pixel value of a coordinate (i,j) of the reference frame, U and V denote the sizes of blocks used for matching the blocks, and (x,y) denotes the motion vector.
19. A motion estimation device comprising:
a pattern block generating unit generating a current frame pattern block for a current frame block and reference frame pattern blocks for a reference frame block;
a motion vector determining unit calculating the sum of absolute differences (SAD) for candidate pattern blocks corresponding to the current frame pattern block among the reference frame pattern blocks and determining the candidate pattern block corresponding to the SAD satisfying a predetermined condition among the calculated SADs as a motion vector;
a motion compensation unit generating a residual signal using a difference signal between the candidate pattern block corresponding to the motion vector and the current frame pattern block; and
an adding unit adding flag information indicating whether a mean pixel value of the encoded current frame block is included and identification information on the encoding mode to the encoded current frame block as header information,
wherein whether the mean pixel value of the current frame block is included is identified by the flag information.
20. The motion estimation device according to claim 19, wherein when the flag information indicates that the mean pixel value is not included, a mean value of mean pixel values corresponding to n blocks surrounding the current frame block is used as the mean pixel value of the current frame block.
21. The motion estimation device according to claim 19, wherein when the flag information does not contain the mean pixel value and the header information further contains additional information indicating that the mean pixel value corresponding to any block among the blocks surrounding the current frame block should be used, a mean pixel value of the block corresponding to the additional information is used as the mean pixel value of the current frame block.
22. The motion estimation device according to claim 19, wherein the pattern block generating unit:
calculates a mean brightness value of the current frame block and a mean brightness value of the reference frame block;
generates the current frame pattern block by subtracting the mean brightness value of the current frame block from brightness values of the current frame block; and
generates the reference frame pattern blocks by subtracting the mean brightness value of the reference frame block from brightness values of the reference frame block.
23. The motion estimation device according to claim 19, further comprising a unit carrying out discrete cosine transform and quantization to the residual signal.
24. The motion estimation device according to claim 19, wherein the SAD satisfying the predetermined condition indicates the least SAD and the motion vector determining unit calculates the SAD with the following equation:
NewSAD
\u2061
(
x
,
y
)
=
\u2211
i
=
0
U
–
1
\u2062
\u2211
j
=
0
V
–
1
\u2062
\uf603
f
\u2061
(
i
,
j
)
–
M
curr
–
r
\u2061
(
i
+
x
,
j
+
y
)
–
M
ref
\uf604
where Mcurr denotes the mean pixel value of the current frame block, Mref denotes the mean pixel value of the candidate pattern blocks, f(i,j) denotes a pixel value at a coordinate (i,j) of the current frame, r(i+x,j+y) denotes a pixel value of a coordinate (i+x,j+y) of the reference frame, U and V denote the sizes of blocks used for matching the blocks, and (x,y) denotes the motion vector.
25. The motion estimation device according to claim 19, wherein the motion compensation unit calculates the residual signal with the following equation:
NewR
\u2061
(
i
,
j
)
=
f
\u2061
(
i
,
j
)
–
M
curr
–
r
\u2061
(
i
+
MV
x
,
j
+
MV
y
)
–
M
ref
=
f
\u2061
(
i
,
j
)
–
r
\u2061
(
i
+
MV
x
,
j
+
MV
y
)
–
M
curr
+
M
ref
\u2003
where NewR denotes the residual signal, Mcurr denotes the mean pixel value of the current frame block, Mref denotes the mean pixel value of the candidate pattern blocks, f(i,j) denotes a pixel value at a coordinate (i,j) of the current frame, r(i,j) denotes a pixel value of a coordinate (i,j) of the reference frame, U and V denote the sizes of blocks used for matching the blocks, and (x,y) denotes the motion vector.