Applications in Single-phase to Three-phase Conversion - Control of Power Inverters in Renewable Energy and Smart Grid Integration - page 225

Transformer

v a

a

i

L a

v b

~

b

v

v c

c

Q 1 Q 3 Q 5 Q 7 Q 9

L

L L L

C

V DC

C

Q 4 Q 6 Q 8 Q 10

Q 2

Figure 14.3 Single-phase to three-phase converter with a universal active power filter. Source: Cipriano
dos Santos et al . 2011

14.2 The Topology under Consideration
According to the analysis in Chapters 10-13, an independently-controlled neutral leg is able
to maintain a stable and balanced neutral point that is the mid-point of the DC link. This can
be applied to form a single-phase to three-phase converter with three independent phases.
Moreover, this neutral line can be shared with the single-phase supply to reduce the number
of power semiconductor switches needed. The resulting topology is shown in Figure 14.4.

Rectifier
Leg

Neutral
Leg

Phase
Leg b

Phase
Leg c

i a

v a =v

a

Q 7

Q 1 Q 3 Q 5

C N+

i b

v b

v fb b

L

N

V DC

L a i L i C

i s L s L r

L

i c

v c

i

v fc c

i r

C N-

~

v

Q 2 Q 4 Q 6 Q 8

C

C

N

Figure 14.4 The single-phase to three-phase converter under consideration