POLITECHNIKA WARSZAWSKA

4. ANN based Current Controllers
4.4. Optimal mode ANN CC
4.4.1. Optimal mode CC
In the case of such a type of controller an optimal algorithm in every sampling
interval T s selects voltage vector that minimise RMS current error (see the section 4.2.
as well). This is equivalent to selection the available inverter voltage vector that lies
nearest to command vector u Sc (t). The command vector is calculated by assumption
that the inverter voltage u Sc (t) and EMF voltage e r (T) of the load is constant over the
sampling interval T s . Based on the calculated u Sc (t) value the voltage vector selector
chooses the nearest available inverter voltage vector (Fig. 4.31.)
u s
synch.
RDCL
i sc
i s
+
-
e r
T
Calculation
of voltage
command
vector
u sc
Voltage
vector
selector
VSI
load
model
3 ph.
load
Fig. 4.31. Optimal discrete modulation controller
Desired voltage vector can be calculated using motor parameters r s , l σ and
electromotive force EMF according to the following equations:
l
u σ
s αc
= ( isαc
− isα
) + rs
isαc
+ eα
(4.9a)
∆t
85