POLITECHNIKA WARSZAWSKA

4. ANN based Current Controllers
not going to zero vector the Pulse Polarity Consistency Rules (PPCR) is violated. To
eliminate these disadvantages and force the NN regulator to select zero vectors and
only adjacent active vectors a modified sampling technique is proposed (Fig. 4.12.).
a)
ε A
K
S&H
S A
ε B
K
S&H
S B
ε C
K
S&H
S C
b)
SH A SH B
SH
C
Fig. 4.12. Improved NN regulator : a) block scheme, b) modified sampling technique
When the sign of the NN outputs signals are sampled not at the same instant but with
a phase shift (Fig. 4.12b) i.e.2π/3, the regulator output signals S A
,S B
,S C
can have the
same values. The inverter under such control operates as shown in Table 4.4. and
illustrates in Fig. 4.14.
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