Christoph Haederli - Les thèses en ligne de l'INP - Institut National ...

22 ML Converter Topologies
1
3
2
(a) (b) (c) (d)
Figure 26, 3-L ANPC (a) and 5-L ANPC type 1 (b), type 2 (c) and type 3 (d)
TABLE 5, FEATURES OF THE GENERALIZED ML ANPC CONVERTER
1. Different number of flying capacitor commutation cells N1, N2 and M for the cells 1, 2
and 3 can be used in a general approach (N1, N2, M all >=1).
2. The number of capacitor required per cell stage is N-1, the number of resulting output
levels per stage is N+1
3. Not all switches in a chosen configuration require the same blocking voltage. The
blocking voltage depends on the number of cells within one stage. As N and M may be
different, blocking voltage requirements may be different. This can be achieved by the
application of different devices or by a series connection of switches.
TABLE 6, OVERVIEW OF GENERAL ML ANPC IMPLEMENTATIONS
Cell numbers Description Comments
N = M = 1 3-L ANPC In contrast to the NPC, the 3 level version of the ANPC
allows for loss balancing [22].
N = 1, M >= 2 ML ANPC type 1
Figure 26 (b)
N >= 2, M = 1 ML ANPC type 2
Figure 26 (c)
stacked MC
converters
N = M >= 2 ML ANPC type 3
Figure 26 (d)
Minimized capacitor count. The input stages are only
used to switch between top and bottom input. High
frequency modulation is done in the output stage only.
The DC link stages consist of MC converters. These
operate at high frequency modulation. The output
stage is only used to switch between the two MC
converters. This results in similar operating schemes as
for the SMC.
There is increased redundancy, which can be used for
control performance or loss distribution. All stages can
be operated either individually (to redistribute losses)
or all together (to have an impact on the NP current).
Interleaved operation allows for higher apparent output
frequency, given a maximum device switching
frequency.