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

110 NP Control with Carrier based PWM
5.3 SMC and ANPC modulation using extra redundant states
Novel modulation schemes making use of redundant states are proposed for SMC and ANPC
(topology specific). These are operating several converter stages simultaneously (opposed to the
schemes in TABLE 82). The modulation schemes in this paragraph are constrained to optimum
modulation. The purpose of these new schemes is:
- Extending the zero NP current areas to allow NP voltage “ripple free” operation in a wider
area.
- Increasing the NP control capacity (range of possible NP current amplitudes) to improve
controllability of the NP voltage.
5.3.1 ANPC type 3 modulation
A simple modulation concept for the ANPC type 3 has been introduced in 4.6.3.2 making use
of the different MC converter stages by alternating between the modulation of a stage at the DC
link and the modulation of the output stage. This simple concept does not make full use of the
available state in the ANPC type 3. There is much higher redundancy than in the ANPC type 1 and
2 and this can be used effectively for an improved NP control. Figure 70 shows the physical
relevance of the additional states and TABLE 43 gives the key properties.
TABLE 43, 5-L ANPC TYPE 3 STATES AND CORRESPONDING VOLTAGES AND CURRENTS
Nr. Type Cell 1 Cell 2 Cell 3 Cell 4 U out I NP I FC1 I FC2 I FC3
0 all 0 0 0 0 -U DC/2 0 0 0 0
1 1 0 0 0 1 -U DC/4 0 0 0 -
2 1 0 0 1 0 -U DC/4 1 0 0 +
3 all 0 0 1 1 0 1 0 0 0
4 2 0 1 0 0 -U DC/4 0 0 - 0
5 3 0 1 0 1 0 0 0 - -
6 3 0 1 1 0 0 1 - 0 +
7 2 0 1 1 1 +U DC/4 1 - 0 0
8 2 1 0 0 0 -U DC/4 1 0 + 0
9 3 1 0 0 1 0 1 0 + -
10 3 1 0 1 0 0 0 + 0 +
11 2 1 0 1 1 +U DC/4 0 + 0 0
12 all 1 1 0 0 0 1 0 0 0
13 1 1 1 0 1 +U DC/4 1 0 0 -
14 1 1 1 1 0 +U DC/4 0 0 0 +
15 all 1 1 1 1 +U DC/2 0 0 0 0